Verify that your SMTP service is allowing connections (looks like your SMTP service should be hosted on local machine from error 127.0.0.1:25 localhost=127.0.0.1 SMTP well known port=25)
Quote:
An existing connection was forcibly closed by the remote host.]
This shows that your SMTP service might be rejecting your connection for some reason.
Depending on your SMTP service
1) check to see if relaying is allowed
2) check to make sure connections are allowed from localhost
3) if you have black list check and make sure 127.0.0.1 isn't blacklisted
4) check if smtp authentication is required
5) sometimes depending on anti-virus SMTP service might be blocked
etc.