Not able to send or receive mail using thunderbird.

Hello I am not able using thunderbird.
This is error I got
Sending of the message failed.
An error occurred while sending mail: Unable to establish a secure link with Outgoing server (SMTP) using STARTTLS since it doesn’t advertise that feature. Switch off STARTTLS for that server or contact your service provider.
What should I do?
As I tried to use webmail also I am not able to send it.
Thanks for your help.

Paste your mail log (tail -100 /var/log/maillog)