What OS are you using? what version of Thunderbird are you using? Did you get the download for Thunderbird from the official webpage: https://www.thunderbird.net/en-US/thunderbird/all/

OR did you get it from Windows App Store, Snap etc ?

re :I have reinstalled Thunderbird twice (both with and without uninstalling first).

There are very few reasons that a reinstallation will fix an issue because the problem must be with the program in order for it to work. Many people do try a reinstall and it usually fails because nothing is wrong with the program. Usually the issue is within the Profile or setup of account and that has nothing to do with actual program itself.

re: I have deleted the accounts and set them up again.

After removing the accounts via Account Settings, did you make sure all mentioning of passwords for those accounts were completely removed as well - do not edit the password - completely remove everything.

• Access Settings > Privacy & Security
• scroll down to passwords section
• Click on 'Saved Passwords'
• Delete/remove all lines that mention both yahoo email addresses.

Then exit/close Thunderbird, wait a few moments and then restart Thunderbird? This would be done to ensure all background processes and files were properly updated.

re :I have changed passwords on the accounts.

You say you changed passwords, but humour me...can you confirm the following: You changed passwords via webmail before you recreated the accounts. Each email address should have it's own unique password in order to access webmail account for each email address. Please confirm each email address does have it's own unique password - you are not using the same password for both email addresses.

You mention 'Yahoo'. Are you setting up IMAP accounts ? I presume yes. Are these email addresses using a yahoo email address eg: @yahoo.com? OR something else eg: an old verizon email address? When creating accounts, did each get set up using: 'Authentication Method' as 'Oauth2' ? Did Thunderbird auto locate all the server settings? If yes: Did you get asked by yahoo for confirmation to allow Thunderbird access to server? If no: You may need to remove the accounts and stored passwords - access both webmail accounts and remove the allowed Thunderbird app in order to force a new request.

It would be helpful if you could post server info. Images that show 'Account Settings' > 'Server Settings' for the accounts. In Thunderbird, Help > TRoubleshooting Information scroll down to 'Mail and News Accounts' - copy all the data and paste it into this forum question.

Thank you so much for your prompt and effective advice. In short deleting the saved passwords bypassed whatever else is happening...which I believe to be the fact that Yahoo was given the wrong account to authenticate. see below.

SInce you took the time to think about this and ask very good questions/explanations.. i figured you deserved the courtesy to get the answers in hopes that whatever is going on here can be corrected.

What OS are you using? * Windows 11 what version of Thunderbird are you using? * 141.0 Did you get the download for Thunderbird from the official webpage: https://www.thunderbird.net/en-US/thunderbird/all/ * yes'''

OR did you get it from Windows App Store, Snap etc ? * no

re :I have reinstalled Thunderbird twice (both with and without uninstalling first).

There are very few reasons that a reinstallation will fix an issue because the problem must be with the program in order for it to work. Many people do try a reinstall and it usually fails because nothing is wrong with the program. Usually the issue is within the Profile or setup of account and that has nothing to do with actual program itself. * you are correct. following other advice i went into the about:profiles page and set up a new profile for the second yahoo account and opened that in a new window. There was no longer a conflict between the two accounts and I was able to see both sets of emails via two windows. Workable but not optimal.

re: I have deleted the accounts and set them up again.

After removing the accounts via Account Settings, did you make sure all mentioning of passwords for those accounts were completely removed as well - do not edit the password - completely remove everything.

Access Settings > Privacy & Security scroll down to passwords section Click on 'Saved Passwords' Delete/remove all lines that mention both yahoo email addresses. Then exit/close Thunderbird, wait a few moments and then restart Thunderbird? This would be done to ensure all background processes and files were properly updated.

* BINGO! This seemed to do the trick. For some reason when I go to set up the second Yahoo account there is a miscommunication between Thunderbird (who is trying to set up B@yahoo.com) and the Yahoo login service who thinks its working on A@yahoo.com. Hence the wrong emails get delivered. After removing the saved passwords it appears (so far) to avoid that miscue.

re :I have changed passwords on the accounts.

You say you changed passwords, but humour me...can you confirm the following: You changed passwords via webmail before you recreated the accounts. Each email address should have it's own unique password in order to access webmail account for each email address. Please confirm each email address does have it's own unique password - you are not using the same password for both email addresses. * consider yourself humoured

You mention 'Yahoo'. Are you setting up IMAP accounts ? I presume yes. * yes Are these email addresses using a yahoo email address eg: @yahoo.com? OR something else eg: an old verizon email address? * mix of rogers.com and yahoo.com * of interest perhaps is that there is no problem setting up multiple gmail accounts

When creating accounts, did each get set up using: 'Authentication Method' as 'Oauth2' ? * yes Did Thunderbird auto locate all the server settings? * yes If yes: Did you get asked by yahoo for confirmation to allow Thunderbird access to server? * yes but, as I reported above, yahoo was confirming the incorrect account. However I didn't notice this when I originally posted the problem If no: You may need to remove the accounts and stored passwords - access both webmail accounts and remove the allowed Thunderbird app in order to force a new request.

It would be helpful if you could post server info. Images that show 'Account Settings' > 'Server Settings' for the accounts.

* i think these are fine because individually the default settings that Mozilla provides work. Server name, user name, port #, SSL/TLS and OAuth2

In Thunderbird, Help > TRoubleshooting Information scroll down to 'Mail and News Accounts' - copy all the data and paste it into this forum question.bold text

account1 (imap) imap.mail.yahoo.com:993 SSL/TLS OAuth2 smtp.mail.yahoo.com:465 SSL/TLS OAuth2 true account2 (none) Local Folders None Normal password account3 (imap) imap.gmail.com:993 SSL/TLS OAuth2 smtp.gmail.com:465 SSL/TLS OAuth2 true account4 (imap) imap.mail.yahoo.com:993 SSL/TLS OAuth2 smtp.mail.yahoo.com:465 SSL/TLS OAuth2 true'''''

I have to say, I don't understand a) how emails could end up in the wrong account, b) how deleting passwords would resolve this.