Mail not working after OSX update yesterday

[Zapdoc]

Cannot send mail on Mail program since update yesterday
Checked BTInternet server and it is OK
Any idea how to fix please ?

 

[Howard2k]

Is there an error message or anything? I'm assuming the computer still turns on?

 

[Zapdoc]

Is there an error message or anything? I'm assuming the computer still turns on?

Computer works well otherwise and the new OSX is nice.
Only Apple Mail program using Btinternet or Yahoo Nail does not receive mail - I can send mail OK
i Cloud mail is OK
Checked the Yahoo / Btinternet web mail and everything is OK ie send and receive mail ok
[doublepost=1539114486][/doublepost]This is message
(62523B12-5236-41BE-B72A-706099536C6D) [Disconnected] lost connection to socket