I am using Windows Live Mail 2011 and have recently upgraded to Windows 10.  I use AVG.

Up until last week I had no problem sending and receiving e-mails with Windows Live Mail 2011.  On Wednesday 25/5 or Thursday 26/5 I stared having problems as the program would receive but not send e-mails.  The settings are exactly the same as they were when I first set up Windows Live Mail in 2011 or 2012.  The message I get is  "Your SMTP server has not responded in 60 seconds.  Would you like to wait another 60 seconds for the server to respond?"  Then I get a choice of Wait or Stop.  If I click on Stop it will stop trying to send e-mails and go on to receive e-mails (which It appears to do correctly).

I have checked with my provider who tells me that there is no problem with my account (as I am able to access the webmail and send and receive e-mails from there) and that the problem appears to be with Windows Live Mail 2011.

I have gone as far as to disable my Internet Security to check whether an update to AVG may have been causing a conflict, but it makes no difference.

If it helps I also get the following:  

Subject "

Server Error: 421

Server Response: 421 4.7.0 mta1.gibtelecom.net closing connection

Server: 'mail.gibtelecom.net'

Windows Live Mail Error ID: 0x800CCC67

Protocol: SMTP
Port: 25

Secure(SSL): Yes

Can anybody help?  Thanks.