I have a similar problem. Ctrl-Enter pops the confirm send dialog. Then if I click "Send" the email does not send, and the compose email email window remains open. It takes several tries before the send process actually completes.

TB 91.2.0 Windoze 10

Still an issue in 91.2.1

The behavior is similar to when no address at all is entered into the To: field although the address written is clearly displayed. The Send option lights up but it won't Send the message.

The Tools -> Address Book tab does not display any email addresses or lists, and it will not allow me to create any new email addresses or lists.

If I enter the address of a personal email list and right-click to Expand List, all of the addresses in that list are written into the To: field. TB 91.2.1 still acts as though no address is written there since it still won't Send, and the window header says "Write: (no subject)" even though there is text in the Subject line.

Another TB user on the same computer (with a separate profile) has no problems at all sending email messages.