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Gmail authorises access but Thunderbird on Linux fails

Check OAuth handoff, package type and profile separately when Google authorises access but Thunderbird cannot connect.

Source date: 5 November 2026Editorial team: KAN KAI WORKSEditorially updated:

Quick answer

A successful Google sign-in in the browser does not prove successful handoff to Thunderbird or access to mail. Identify the active Thunderbird installation and profile, then record the exact stage where the return fails. The Linux report contains different results with Snap and other packages. It therefore does not establish a universal Snap defect; version, profile and applicable Workspace influences require separate checks.

Source basis: Q1 · Q2 · Q3

Applies to
Covers Gmail OAuth in Thunderbird on Linux, starting from a version 159 report. Packaging and browser handoff behavior vary; a general package defect is not established.
How to verify the result
The intended Thunderbird instance receives authorization for the correct Gmail account, and an actual message retrieval confirms access beyond the browser's success message.
Your first check

Does browser authorisation return to the intended Thunderbird instance?

Record version, package type and the last successful OAuth step. A Google confirmation in the browser does not establish a working mail connection.

Google confirms sign-in and authorisation in the browser, but Thunderbird on Linux still reports Authentication failure. Re-entering the password does not help. A Thunderbird 159 report describes this with a Snap installation, while other replies describe working Snap installations. That evidence does not justify a general instruction to uninstall Snap. Q1

Observe three separate stages

Google sign-in, delivery of authorisation back to the application and access to the mailbox are distinct stages. Mozilla's current Gmail guide describes the OAuth sequence and distinguishes older Thunderbird versions. Q2 A successful browser confirmation establishes only the part of the process visible in that browser.

Investigate the handoff

  1. Identify one active instance. Record the running version, distribution source and package type. Check for multiple installations or profiles. The browser return should not accidentally launch or target a different Thunderbird installation.
  2. Locate the failure in the sequence. Does it occur before Google sign-in, during consent, on return to Thunderbird or during the first mailbox operation? Preserve the exact wording. Remove authorisation codes and tokens from anything shared for support.
  3. Compare account configuration. Check the intended Gmail endpoint and documented OAuth method. Distinguish a personal Gmail account from a managed Workspace account whose administrator may impose additional access rules.
  4. Observe the browser return. Run one fresh authorisation and note which application becomes active and whether a local callback or protocol association visibly fails. Changing the password does not answer a failure in this return step.
  5. Prepare an isolated comparison. If necessary, back up the existing profile and test a separate profile or supported package variant. Mozilla documents that profile data is stored separately from application files. Q3 Do not open the same existing profile simultaneously from two application instances.

Act on the difference you observe

If only the isolated comparison works, examine differences in browser integration, permissions and profile state. Preserve local folders and other stored data before planning a package change. Successful account creation in a test profile does not establish that all previous mail and settings have been migrated.

For handoff, provide the precise sequence, version, package format, browser and a sanitised error excerpt. Keep profile backups private: they may contain sensitive messages and account information. Record any changed settings so that the comparison can be reversed without losing the original baseline.

Frequently asked questions

Is my Google password wrong?

A successful browser sign-in argues against that simple explanation. Identify the later stage at which the process fails.

Should I copy every OAuth preference from a forum?

No. Such preferences can be version-dependent. Use a limited comparison and document each change.

Describe your case

Support with this issue

We can review the OAuth sequence and prepare an isolated profile or package comparison.

Describe your case →Related service: Data & improvements

Sources