Signing Email Deliverability: Get E-Signature Requests to the Inbox

A signing request that lands in spam is a contract nobody signs. Signing email deliverability is the share of your e-signature invitations, reminders and completion notices that reach a recipient’s inbox after their mail server accepts them. You improve it by authenticating your sending domain, keeping complaints low, writing plain and recognizable messages, and watching placement with real data instead of assuming “sent” means “seen.”

This guide walks through the causes, the checks and the fixes, in the order you would work through them.

TL;DR

• Delivery means the recipient’s server accepted your message. Deliverability means it reached the inbox instead of spam or quarantine. Signing emails need the second one.
• Authenticate the domain your signing emails come from with SPF, DKIM and DMARC. Without that, mailbox providers have little reason to trust you.
• Keep user-reported spam below 0.1%, and watch it in Google Postmaster Tools.
• Write signing emails that look like a message from a person you know: a clear sender name, a specific subject, one call to action.
• Test with real inboxes at the companies your signers work for. Corporate filters behave differently from Gmail.

Table of Contents

• Delivery and deliverability are not the same thing
• Why signing emails miss the inbox
• Set up SPF, DKIM and DMARC for signing emails
• How to check whether your signing emails reach inboxes
• Write signing emails that filters and people trust
• Manage recipients and volume
• What to do when signing emails go to spam or bounce
• Our perspective: own the sender, own the outcome
• Run signing under your own domain with BeeSign
• Frequently asked questions
• Sources

Delivery and deliverability are not the same thing

Your e-signature tool may report “sent” or even “delivered.” That status usually means the receiving mail server accepted the message. Klaviyo’s help center draws the line this way: delivery is the successful transfer to the recipient’s server, while deliverability is where the message lands afterward, ideally the primary inbox and not spam.

The distinction matters more for signing than for newsletters. A marketing email that goes to spam costs you a little engagement. A signing request that goes to spam can hold up a lease, an offer letter, a vendor agreement or a student enrollment. The signer never knows the document exists, and you see only a pending status.

Mailbox providers act as gatekeepers here. As Proofpoint explains, deliverability is built on trust: receiving providers weigh authentication, sender reputation and past behavior before deciding where an accepted message belongs.

Why signing emails miss the inbox

Signing emails have traits that spam filters notice. They are automated, they often carry a link to a document or a PDF, they come from a platform’s infrastructure rather than a person’s mailbox, and they ask the recipient to act. Recipients who have never heard of you tend to ignore or report them.

According to Klaviyo’s guidance, the main factors are:

• Sender authentication (SPF, DKIM, DMARC)
• Sending reputation
• Complaint and engagement history
• Sending volume and patterns
• Message content
• The sending domain, IP and tracking infrastructure

Here is how each plays out for a signing workflow.

Authentication does not match the visible sender

If an email says it comes from [email protected] but is actually sent by a platform that your domain’s DNS has never authorized, filters see a mismatch. That pattern looks like spoofing, and spoofing is exactly what filters are built to catch. The FTC advises small businesses to make sure their email provider uses SPF, DKIM and DMARC so scammers cannot impersonate their domain.

Reputation is shared or unknown

When a platform sends for thousands of customers from the same domain, your reputation is partly tied to everyone else’s behavior. When you send from a brand-new domain with no history, you have no reputation at all. Either way, the first few hundred messages matter.

Recipients report or ignore the message

Complaints are the loudest signal. Google tells senders to keep their user-reported spam rate below 0.1% and to avoid reaching 0.3%, the point where inbox delivery suffers more and bulk senders can lose eligibility for mitigation. A signer who does not recognize your company and clicks “Report spam” counts against you.

The recipient’s own policies intervene

Correct authentication does not guarantee placement. Transactional email can still be quarantined by recipient policies, including Microsoft 365 Defender or Exchange mail flow rules. This is common when your signers work at larger companies, banks or schools. Nothing you change in your own DNS will fix a rule that sits on their side. You need their IT team to allow your sender.

The sending infrastructure has a bad history

Providers reject mail from sources they consider abusive. Yahoo, for example, states that open proxies and open relays are common sources of spam and that it does not accept email from them. If your signing platform or a connected system relays mail through an unsecured server, bounces follow.

Set up SPF, DKIM and DMARC for signing emails

These three DNS-based checks tell mailbox providers that the platform sending your signing emails has your permission.

A practical order of work

1. Decide which address signing emails come from. A dedicated subdomain such as a signing or contracts subdomain keeps signing reputation separate from your marketing and staff email.
2. Add the platform’s SPF include to your domain’s existing SPF record. Do not publish a second SPF record. Two records invalidate each other.
3. Publish the DKIM key your platform gives you as a DNS record, then confirm the platform shows it as verified.
4. Publish a DMARC record at p=none with a reporting address. Read the reports for a few weeks, fix any legitimate source that fails, then consider tightening the policy.
5. Send a test to a Gmail address and open the original message headers. Look for PASS next to SPF, DKIM and DMARC.

Google sets a floor for large senders. Those sending 5,000 or more messages a day to personal Gmail accounts must authenticate with SPF and DKIM and publish a DMARC policy of at least p=none, plus valid forward and reverse DNS records, TLS encryption and RFC 5322 message formatting, per Gmail’s sender guidelines. Most signing senders are far below that volume, but the same checks are what filters look for at any volume.

A branded sending setup helps here, because the domain a signer sees matches the domain your DNS vouches for. We cover the portal side in our guide to setting up a branded signing portal and explain the trust benefits in why custom domain document signing matters.

How to check whether your signing emails reach inboxes

A “delivered” status cannot tell you whether the message sat in the inbox or the junk folder. You need other evidence. Use several of these together.

Watch Google Postmaster Tools

If your signers use Gmail or Google Workspace, add your sending domain to Postmaster Tools. Its dashboards show your spam rate, IP and domain reputation, the share of mail passing SPF, DKIM and DMARC, encryption, and delivery errors. Gmail calculates spam rates daily and updates them there, so you can see a problem within days instead of after a quarter of unsigned contracts.

Postmaster Tools shows meaningful data only when you send enough volume. A small team may see empty dashboards. In that case, rely on the manual checks below.

Read your DMARC reports

Aggregate DMARC reports list which servers sent mail as your domain and whether it passed authentication. They quickly reveal a forgotten tool sending with your address, or a platform whose DKIM is not aligned.

Run seed tests with real inboxes

Create test accounts at the providers your signers use: Gmail, Outlook.com, Yahoo, and if possible a Microsoft 365 business tenant. Send a real signing request to each and note where it lands: primary inbox, a tab, spam or nowhere. Repeat after any change to your DNS, template or sending domain.

Track the signals inside your signing tool

For each document, compare the time from sent to opened with the time from sent to signed. A pattern of documents that are never opened, mixed with a handful that sign within minutes, points to placement problems at certain providers. Bounces and complaint notices tell you about the sender, and silence tells you about the filter.

Ask the signer

It sounds basic, but a short phone call to a stuck signer, asking them to check spam and quarantine, resolves many cases. Note which email domain it was and add it to your seed test list.

Write signing emails that filters and people trust

Authentication gets you through the front door. Content and recognition decide the rest.

• Use a clear sender name. “Maria at Northside Property Management” beats “no-reply.” Recipients open what they recognize.
• Write a specific subject line. Name the document and the sender: “Lease agreement for 14 Oak Street, ready for your signature.” Avoid urgency tricks and all-caps.
• Keep the body short. Say who you are, what the document is, what the signer needs to do and how long it takes.
• Use one main link. Many links, link shorteners and mismatched link domains look like phishing.
• Announce the email beforehand. Tell the signer in person, by text or in your onboarding steps that a request is coming from your company. This is the cheapest deliverability fix there is.
• Offer a reply path. A monitored reply address signals a real sender and lets a confused signer reach you instead of reporting spam.
• Keep signing mail separate from promotion. Do not add banners, offers or newsletter blocks to signing messages. Promotional content in a transactional email can pull its placement down.

If you want a broader view of why mail accepted by a server still ends in junk or quarantine, this overview of business email deliverability covers the common causes.

Manage recipients and volume

Good habits at the list level protect your whole domain.

Verify addresses before sending. A typo in a signer’s address produces a hard bounce. Too many bounces damage reputation, so correct the address and resend instead of retrying the same one.

Send only what was requested. Each signer should expect your message. Reminders are fine at a sensible pace, and a sequence that sends five reminders in a day invites complaints.

Ramp up gradually. If you are moving from a handful of documents to hundreds, increase volume in steps. Sudden spikes from a new or quiet domain look suspicious. When you plan large batches, our guide to bulk sending e-signature requests with CSV templates explains how to structure them.

Clean up unresponsive addresses. If a contact has never opened any request, stop sending reminders to the same address and try another channel.

What to do when signing emails go to spam or bounce

Work from the cheapest fix to the most involved.

1. Confirm the failure. Is it one recipient, one company, or one mailbox provider? A single recipient points to a local rule. A whole provider points to your reputation or authentication.
2. Read the bounce message. The error code and text usually name the reason: authentication failure, policy block, mailbox full or unknown user.
3. Recheck SPF, DKIM and DMARC in the headers of a fresh test email.
4. Check your complaint rate in Postmaster Tools. Anything near the 0.1% mark means you should review who is receiving your requests and how they are introduced.
5. Ask the signer’s IT team to allow your sending domain if the recipient works at an organization with strict filtering, and give them the exact domain and sending addresses. Quarantine at Microsoft 365 tenants is released by their administrators.
6. Offer another route. A signing link shared through a secure message or text, or an embedded signing page on your own site, bypasses the inbox altogether. See our embedded e-signature integration example for how that works.

If your signers are in a locked-down network, IP allowlisting may come up as a request. Read what IP whitelisting for e-signature covers and where it stops before you promise it.

Our perspective: own the sender, own the outcome

Most deliverability trouble in signing comes from one gap: the person receiving the email sees one brand, while the mail infrastructure belongs to another. A signer gets a message from a platform name they have never heard of, with a link to a domain they do not recognize. A careful person hesitates. A filter does the same.

That is why we built BeeSign around white-label operation. When you run signing under your own branding, custom domain and branded emails, the sender, the link and the page the signer lands on all point back to you. Mailbox providers can see consistent signals, and signers can see a company they already know. Bring-your-own-cloud storage extends the same principle to documents: your data stays in your infrastructure.

We also think deliverability is partly a process problem and not only a DNS problem. Tell your signers a request is coming. Keep signing mail free of marketing. Check inbox placement as part of rolling out any new template. Treat a stalled document as a signal to investigate, not a reason to resend three times.

— Mustafa Abusharkh

Run signing under your own domain with BeeSign

If your signers keep asking “is this email real?”, the fix is to make the email unmistakably yours. BeeSign’s White Label & BYOC option lets you run the service with your own branding, custom domain and branded emails, with storage in your own cloud. You can see how our electronic signature product handles requests and templates, or check plans and pricing: the Individual plan is $9.99 per month, and Enterprise and custom integration needs are quoted separately. Every plan starts with a 7-day free trial, so you can send test requests to your own seed inboxes before you commit.

Frequently asked questions

What is the difference between email delivery and email deliverability?

Delivery means the recipient’s mail server accepted your message. Deliverability describes where the message went after that: the inbox, a tab, spam or quarantine, according to Klaviyo’s definition. For signing, only inbox placement gets the document signed.

Why do my e-signature emails go to spam when the status says delivered?

The status only confirms that the server accepted the message. The filter then judges authentication, sender reputation, complaints and content. A mismatch between the visible sender and the authorized sending service is the most common fixable cause, followed by recipient-side quarantine rules at business mail systems.

Do I need SPF, DKIM and DMARC for signing emails?

Yes, in practice. The FTC recommends that businesses use all three to protect their domain from impersonation, and Gmail requires them from bulk senders. Even at low volume, passing all three removes a major reason for a filter to distrust your message.

How can I tell if signing emails are landing in inboxes?

Combine Postmaster Tools, DMARC reports, seed tests with real accounts at your signers’ email providers, and the open-to-sign timing in your signing tool. No single signal is complete, so use at least two.

Sources

• Understanding email deliverability, Klaviyo Help Center
• What Is Email Deliverability?, Proofpoint
• Cybersecurity for small business: Email authentication, FTC
• Email sender guidelines FAQ, Gmail Help
• Postmaster Tools dashboards, Gmail Help
• SMTP Error Codes, Yahoo Sender Hub
• Why transactional emails get blocked by Office 365, Suped

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