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.

[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