SMTP settings in TB as shown in the server settings section for each account are all correct.

But what are they.

I have found over the years that the vast majority of folk asserting the settings are correct are actually not correct in their assumption. For instance, does the outgoing server (SMTP) entry in account settings have authentication as being required?

Matt, thanks for getting back to me. Settings are indeed correct. Anyway they are all unchanged by me from the time I set up TB. They all worked fine in the interim, and remain unchanged. Server name is correct as is security (SSL/TLS, to put your mind at rest); Port 465; and authentication method is normal password. All was well until suddenly it wasn't. I would be most grateful if you could suggest possible causes and appropriate remedies Thanks

For example, why are passwords no longer stored? I have never deleted them!

Just to say that passwords now seem to be able to be saved in the Privacy & Security section again. They were certainly not there yesterday, otherwise I would not have raised a query. All I did in the interim was to shut down overnight and restart a short time ago. I had to enter pop3 passwords to receive emails on all the accounts, and tried the smtp one again to see what might happen; surprise - it worked! The puzzle remains though as to why they disappeared in the first place. What glitch occurred to cause them to be deleted, and stay unsaved for the whole session? And why in the first instance only the smtp ones? Is this something for the great people who add bits to make TB better?