Chosen Solution

In the Options...Saved Passwords window, click Show Passwords, then right-click an entry, Edit Password.

This method does not work, I have no Outgoing SMTP password. Is there another way to add it to Thunderbird 52. Thanks

@sfhowes The given solution worked for almost two months, then today send messages did not go through. I went through the steps to change the password and send now works again. Do we know what triggers TB to ask for the password after it has worked for this long?

Thanks for your help. I would not have got it to let me send messages without your help.

sfhowes said

I suppose it's possible that if you use a firewall other than the Windows Firewall, and TB is updated, as it was this week, then you have to adjust the firewall to allow TB to send. Perhaps resetting the password accomplishes this.

I use the Windows Firewall. Still, apparently your method for resetting the password works anyway.

Do you think that every TB update will trigger having to reset the password?

Thanks for your help. Knowing how to fix this saves a bunch of time and trial-and-error troubleshooting.

Thanks.

Where Do I find Options Im using ver 52,5,4 on an iMac

Preferences instead of options when using a Mac. Read this for menu differences between operating systems. http://kb.mozillazine.org/Menu_differences_in_Windows,_Linux,_and_Mac