OK thanks. I just quickly read the link and know how to remove passwords but no idea what these oauth tokens are or how to delete them or edit them. No idea where an OAuth browser window is either unless you mean the little box that pops up when passwords need to be changed or added? I'm only getting the error box but I'll read that thread again later and hopefully it will make more sense and start working again. Thankfully I don't need to be able to send much mail with my 2nd GMail a/c as most goes through my main one and that doesn't have this problem.

OK thank you again for now.

Mancunian_Nick said

OK thanks. I just quickly read the link and know how to remove passwords but no idea what these oauth tokens are or how to delete them or edit them. No idea where an OAuth browser window is either unless you mean the little box that pops up when passwords need to be changed or added? I'm only getting the error box but I'll read that thread again later and hopefully it will make more sense and start working again. Thankfully I don't need to be able to send much mail with my 2nd GMail a/c as most goes through my main one and that doesn't have this problem.

The Oauth browser window appears if the authentication on the account is OAuth2 instead of 'normal password'. This is the default for gmail POP and IMAP accounts as of TB 68.5. After the account password is entered in the browser window, an oauth:// token is stored in the password manager. OAuth authentication avoids issues with allowing 'less-secure' apps in Google or two-step verification and app passwords.

Gregory J Wolfe said

Sending messages was working fine until today 2/22/20 (actually, last verifiable sent message was 2/15/20). Mail supplier is yahoo mail, smtp.frontiernet.net. Spent an hour on the phone with them verifying my Tbird settings. Can successfully send email from the yahoo.com mail web page. When I try to send from Tbird, I get this error: An error occurred while sending mail: The mail server sent an incorrect greeting: 554 5.7.1 <cpe-67-253-178-147.rochester.res.rr.com[67.253.178.147]>: Client host rejected: Access denied. Could this be related to the most recent Tbird software update? Thanks in advance, Greg Wolfe

Changing outgoing server to smtp.mail.yahoo.com fixed the problem but I wanted to comment on a couple other conditions. I took my laptop to a tech help center, was able to send using the frontiernet.net server - the only difference there was the network.

Also don't think it had anything to do with Mozilla because my wife was having the same issue on her iPad. Thanks,

NO SEND PROBLEM FIXED:

This issue turned out to be easily fixed by unplugging the modem/router for 5 or 6 minutes. Plugging the modem/router back in and waiting till you have an Internet connection. Then you need to reboot the computer to obtain a fresh IP address that is not blocked! FIXED IT FOR ME!