Openreach recently installed fibre broadband to my home and since then I'm able to receive emails from my provider, but unable to send or reply to messages from thunderbird.

you go to account settings and in the outgoing server(SMTP) entry you change the authentication to use a normal password.

Hi Matt, thanks for your reply, The only options are:- Connection Security -None, Starttls or SSl/Tls

  on "none" the  Authentication Method :- No Authentication, Password transmitted insecurely, Encripted password, Kereros, Gssp' NTLM

On starttls and SSL/Tls Authentication Method :- Normal Password, Encripted password, Kereros, Gssp' NTLM

I have it set to SSl/tls and "Normal Password"

But nothing seems to work.

I guess you are not in your outgoing server entry.

As you can see the full text is "password transmitted insecurely"

Incoming server have normal password. Bit of a lapse on my part.

I was in outgoing server entry, but there is no option "Password transmitted insecurely" only the ones I said above. However today i have a different problem as I cant download anything and if I try sending an email I get the message " message could not be sent outgoing server timed out, try again"

I'm not sure what's going on, I can once again receive messages into Thunderbird but still get the message that the connection to the outgoing server of my ISP timed out when I try reply or send a message.