Adobe Sign "Authentication Failed" — Fixing Sign-In and Signer Verification Errors

Symptom fingerprint

The exact strings, error codes, and UI surfaces that map to this issue:

First, work out which authentication is failing

"Authentication failed" covers two completely different steps, and the fix depends on which one you're stuck at. Getting this right saves you an hour of chasing the wrong thing.

Account authentication is you logging into Acrobat Sign to send or manage agreements. Signer authentication is a recipient proving who they are before Adobe lets them open a document — via password, phone/SMS code, government ID, or knowledge-based (KBA) questions the sender turned on.

Why account sign-in fails

If you can't get into your own Acrobat Sign account, it's usually one of these:

• Two Adobe IDs — a personal account and a company (Federated/Enterprise) account share the same email, and Adobe picked the wrong one.
• SSO/SAML misconfiguration — your organization uses single sign-on and the identity provider isn't returning the expected assertion.
• A stale browser session holding an old token after your access level changed.
• The account was moved to a different Adobe org or the entitlement lapsed.

Fix account sign-in

Do these in order:

• 1. Go to account.adobe.com and sign out everywhere, then close all Adobe tabs.
• 2. Reopen Acrobat Sign in a private/incognito window and sign in. If Adobe asks "Personal or Company/School account", pick the one your Sign licence is on.
• 3. Reset your password from the login page if the credentials themselves are rejected.
• 4. On SSO: confirm you're launching from your company portal (SP-initiated) or the correct tenant URL. If it still fails, your Adobe admin needs to check the SAML config — mismatched email attribute or an expired IdP certificate are the usual culprits.

Fix signer verification failures

When a recipient sees "we couldn't verify your identity", the sender set an identity check on the agreement and the recipient isn't clearing it. This also happens if the agreement was forwarded to someone other than the named signer.

• Password auth: the sender must share the password separately — it isn't in the email. Ask them to resend it.
• Phone/SMS: the code goes to the number the sender entered. If it's wrong, they need to correct the recipient's number and resend.
• KBA (US knowledge-based): answers must match public records for the named person — a forwarded link to a colleague will always fail.
• Government/Photo ID: allow the camera permission and use good lighting; retries are limited before the agreement locks.
• Make sure the person signing is the exact recipient on the agreement — identity checks are tied to that named signer.

Still not working?

If sign-in and verification both look correct but it still fails, the block is usually environmental or on the sender's configuration.

• Try a different network — corporate proxies and VPNs sometimes break the SSO or verification redirect. Mobile data is a quick test.
• Clear cookies for adobe.com and echosign.com specifically, then retry.
• Sender side: check the agreement's authentication method under Manage → the agreement → recipient settings, and lower it (e.g. from KBA to email) if the signer genuinely can't pass it.
• Enterprise admins: review the SSO/SAML setup and the account's data region if multiple users are affected at once.

You might also need

More fix guides in Adobe Sign and related areas.