Mail server pop.gmail.com responded: Invalid credentials

Google is rolling out changes in its security, you can read about it here https://support.google.com/accounts/answer/6010255

As for Thunderbird's continued access to Gmail, your account settings should automatically change to OAuth2 authentication instead of the old and insecure Normal Password authentication. See https://support.mozilla.org/en-US/kb/automatic-conversion-google-mail-accounts-oauth20

What you will see, when using Thunderbird to download or send mail, is a separate window asking you to sign in to your Google account (Gmail). That (web browser) window is part of the OAuth2 process flow. If for some reason you haven't seen that window yet, open Account Settings via Thunderbird's menu, or right-click your gmail account and select Settings. In the Server Settings section, under the Security Settings heading, you'll see the Authentication method field. Change it to OAuth2.

Thanks, I checked my settings and it was already set to the OAuth2 process flow. As were all my other Gmail accounts which were all working correctly. Only this one was not? so that was not the problem for the separate window not popping up.

I tried resetting it a couple of times, still no pop up.

I then tried sending a new message - this time the pop up did appear asking to allow TB acess to my account thus allowing me to continue.

Open Preferences > Saved Passwords. Check for any Gmail entries that still have your primary Gmail passwords in the Password field instead of an OAuth token and delete them.

Again thanks I still have a problem, when checking mail on this account I continue to get the error message, although I can send mail as normal from it without problems.

I checked and removed any old passwords from this account as you suggested but still the same problem.

(I have several gmail accounts but this one is the only giving problems).

I am now getting this error on another of my accounts when trying to authorise it. Error de autorización Error 403: rate_limit_exceeded

This app has reached its sign-in rate limit for now.

Google limits how quickly an app can get new users. You can try signing in again later, or ask the developer (tb-google-oauth@googlegroups.com) to increase this app's sign-in rate limit.

If you are the developer for this app, you can request a sign-in rate limit increase.

As you can see from that error, it is Google that sets that limit. Give it a while before you try again. With the ongoing switch to OAuth2, a lot of Thunderbird users are signing in to their Google accounts anew, resulting in Thunderbird hitting the limit set by Google. You will be able to authorize the account eventually, just be patient.

As for the other problematic account, you can remove it and add it afresh.

I continue to have this problem and have gone to settings and it already showed OAuth2.

I have gone into saved passwords and deleted all except the OAuth2 dated 22 April and still no joy. As with richard above I can send emails but not receive them still.

I did initially get the google page coming up but it would not accept my Gmail password and also I could not shut the google screen down as as the page could not be moved down for me to delete it!

I'm confused by what I do next from the above so please some "dummy " instructions.

I continue to have this problem and have gone to settings and it already showed OAuth2. I have gone into saved passwords and deleted all except the OAuth2 dated 22 April and still no joy. As with richard above I can send emails but not receive them still. I did initially get the google page coming up but it would not accept my Gmail password and also I could not shut the google screen down as as the page could not be moved down for me to delete it! I'm confused by what I do next from the above so please some "dummy " instructions.

Start your own thread via https://support.mozilla.org/en-US/questions/new

I finally solved this problem by just totally deleting ALL both old and new passwords for the problem account which forced the Google page to appear asking for the login details.

If this had not worked I would have deleted and reinstalled the account as suggested by stans

Thanks Richard, I deleted all passwords as you say and was then able to get the Google page again. However my password was again not accepted. It seems as a long standing user I had only a Thunderbird login which is no apparently is no longer valid. I had to set up a Mozzilla login and then I can now receive emails. Thanks for your help

Re Stans chosen solution "As for the other problematic account, you can remove it and add it afresh."

Stupid question, but what happens to all the stored information etc if I remove the account and the add it afresh under the same e-mail address name? Will Gmail accept the creation of a new account under a recently used name (email address)?

re : if I remove the account and the add it afresh under the same e-mail address name? Will Gmail accept the creation of a new account under a recently used name (email address)?

Yes.

Imap accounts store all messages on the server, so removing an imap account and then adding it again, will pick up all messages on server, although you may need to subscribe to see folders which you created.

Pop accounts store all messages on your computer in the profile folders. Before you remove anything, it would be a good idea to create a backup of your Thunderbird profile. On Windows OS, it is by default here - you would exit Thunderbird and copy the 'Thunderbird' folder to a suitable location eg: external drive: C://Users/Username/Appdata/Roaming/Thunderbird

When you use Account Settings > select name of pop account > clickon Account Actions and select 'Remove account', it only removes the account from the prefs.js file, so it cannot be accessed via Thunderbird. It does not delete the actual pop account files. When you create the account again, it will look new - do not download any messages. Account Settings > Server Settings Bottom right is 'Local directory'...you need to click on 'Browse' which opens shwoing contents of new pop account name folder. Go up to the 'Mail' folder and select the original pop mail account name folder. Note the new pop account is likely to have same name as original but it will have a number added. Then click on 'Select Folder' This will point the new account to use the old pop account files and display all emails again.

I also have the Invalid Credential pop-up, I know what I did wrong but not how to correct it. I have several gmail emails, and each has its own folder and sub-folders in Thunderbird. Things are set up so that TB downloads all emails to my PC and deletes them on the gmail server. Earlier today, I changed the authentication method in TB for each of my my accounts from normal password to Oauth2. I also did the same for the outgoing server. This resulted in several Google popups (one for each email account) asking me to log in and allow TB access.

The popup did not state which email account it related to - it just asked me to log in. So what I did wrong was to assume this was like logging into Google in general, i.e. logging in to any one account gives universal access.

I entered the same email address and password into every one of the popups. E.G. for clarity: email 1 acct: entered email 1 and email 1 password email 2 acct: entered email 1 and email 1 password email 3 acct: entered email 1 and email 1 password and so on.

Google accepted this, but now I can only use the one email account which I entered the correct details for. Clearly, I should have entered the email and password relating to each account into its popup, but anyway there was no way of telling them apart. (Moral for others: edit your accounts one by one!)

How can I reset the emails/passwords entered for my affected accounts?

I have tried setting the authentication method in TB back to normal password and then back to Oauth2, but this did not result in a new popup. I tried sending an email from one of the affected accounts to the good one because someone else said that this resulted in the popup for them, but it did not for me and the email was sent and received without issue.

Any advice welcome. Please use beginner steps!!

re :The popup did not state which email account it related to - it just asked me to log in.

You enter the email address, thus you are choosing the account you want to allow Thunderbird access. But I guess you have figured that out.

Make sure all the Authentication Methods are set to OAuth2 for all accounts both incoming and outgoing smtp.

Let's clear everything, so you can start again.

Menu app icon > Preferences > Privacy & Security Under 'Password' section Click on 'Saved Passwords' select each to highlight and click on 'Remove all'

Restart Thunderbird. google asks for authentication. Enter email address and enter the password for that email address. At next prompt, enter another email address and password for that email address. Repeat for each email address.

Toad-Hall, that's wonderful! I am clearly very rusty, being a set and forget type operator with the emphasis on the second bit - I scoured Acct Settings for password info without luck and would never have thought of looking for it in Preferences (a strange location choice but never mind).

I had to slightly modify your instructions because the G popups only started after I'd entered 2 or 3 passwords and, once again, each popup did not say which account it was asking login details for. I checked carefully!

So although my setup is clearly not normal (!), I will set out below what I did, based on your advice, just in case it helps others.

So I had to start over, deleting all passwords as you explained. Then I set all the server settings to normal password. (Very glad I went through all this before 30 May!). All back to )the old less secure) normal. Next, I reset only one of the email server settings to Oauth2, and then asked TB to check for emails for that email only (instead of checking all accounts at once). That generated the G popup which logically could only relate to the account I'd just changed. I entered the login stuff and it worked. I repeated this for all my other emails, strictly one by one, dealing with each one's G popup and checking that account for new emails before changing the next email to Oauth2. In each case, I did get one new email - a security warning from G. That was useful because it showed that the new settings were working.

When I had done the whole lot, I shut down and restarted TB, and it automatically checked all accounts for emails as it is set to, and I got no error or failed messages.

I haven't yet tried sending emails between my own accounts as a final check, but it would seem that with your help, and clear simple steps, you have got me back in action again.

Many many thanks!