Email authentication issue (Gmail App on phone, Thunderbird on Windows 10 LTSC)

Question

Email authentication issue (Gmail App on phone, Thunderbird on Windows 10 LTSC)

Alex Nash 0

Let me cover the steps I've taken so far.

Thunderbird (laptop) and Gmail app (phone) is up to date.

All IMAP and STMP settings are correct for both devices, OAuth2 works fine in Thunderbird.

I can send emails, irregularly receive them.

Both apps keep telling me there are authentication issues/pop-ups that annoy the hell out of me.

I cannot figure this out myself, with ChatGPT or Claude.

Could it be that I have an old @hotmail.co.uk email address?

GMail phone app says that it can't log in because all the details are incorrect, but they are not because it is exactly what Microsoft publish - I checked at least 10 times.

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Answer 1

Chloe-V 13,620 Microsoft External Staff Moderator

Hi Alex Nash

I understand how frustrating this must be, especially after verifying the settings multiple times.

Since Thunderbird is able to authenticate with OAuth2 and can send emails successfully, this suggests that the account itself and the server settings are likely working correctly.

To help narrow down the issue, may I confirm how the account was added to the Gmail app?

Did you choose "Outlook, Hotmail and Live" and sign in through Microsoft's sign-in page?
Or did you select "Other" and manually enter the IMAP/SMTP settings?

This information will help determine whether the Gmail app is using Microsoft's modern authentication process correctly.

I look forward to your update.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Alex Nash 0 Reputation points

2026-08-14T22:24:35.0033333+00:00

I have tried to use both options in the past when trying to figure this issue out. One obviously works to solve extent (though I don't remember exactly which).

For the Gmail app on my phone, I have 3 separate emails addresses added. The credentials were showing as not correct for one of them to begin with, then another started to it a short time after.

Also, I do not have this issue (with Thunderbird or my phone) with a y of my Gmail addresses.
Chloe-V 13,620 Reputation points Microsoft External Staff Moderator

2026-08-16T23:45:47.6466667+00:00

Hi Alex Nash

Thank you for clarifying. Please remove one affected Hotmail account from the Gmail app and add it again using Outlook, Hotmail and Live, then complete the Microsoft sign-in prompt. Avoid selecting Other, as that may use manual authentication instead of OAuth.

If the issue remains, please provide the exact authentication message, with personal details hidden.
Chloe-V 13,620 Reputation points Microsoft External Staff Moderator

2026-08-17T23:23:51.14+00:00

Hi Alex Nash

Is there any update from you?

If yes, please feel free to let us know.
Alex Nash 0 Reputation points

2026-08-18T01:12:34.5633333+00:00

I have done these steps before, but I will do them again.

This doesn't change the same issue I am facing with Thunderbird... One thing at a time I guess. I will update you shortly.
Chloe-V 13,620 Reputation points Microsoft External Staff Moderator

2026-08-18T23:11:41.95+00:00

Hi Alex Nash

Thank you for the update. I understand that you have already tried these steps before and appreciate your willingness to test them again.

Once you have had a chance to complete the troubleshooting, please let us know the results. Any additional details you can share will help us better understand the issue and assist further.

We look forward to your update.