Can't send emails after upgrade of Thunderbird

[cblint]

I can receive emails from office365 but am unable to send emails after the recent upgrade.  How do I fix this as I am not very technically savvy?  Before the upgrade I had absolutely no problems and loved Thunderbird.  Do I just have to quit using Thunderbird???

[PaulGrogan]

Same here. It upgraded this morning and now I can't send emails. Receiving them ok.

[Emery]

Same here, upgraded this morning now stuck with the sending problem. Have checked and rechecked smtp server settings and they are OK, always were OK until the update. 

[Lou]

Get this message with any email reply I try to send.

[Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.gmail.com timed out. Try again.] Happens in about 10 seconds.

However, if I delete the original email to which I am replying, the message goes 'almost' immediately. 

In addition, sends are slower than ever, no matter the size. 

All since recent update. 

Gets tiresome having the 'improvements' screw up what usually is a very efficient email program

[Emery]

Have the identical problem but even a new message does not go out.

Updated Thunderbird one hour ago, yikes what a nightmare.

[throma]

A few days ago I had the same issue with error message saying to check my settings. Now I still can't send but can receive and error message has changed to AUP#OUT-1500 , that my email sending address is not the same as my authorized Thunderbird email  address. My email address has been the same for 20 years and it is correct in Mozilla settings!