Please Help..SSRS: Failure sending mail: The transport failed to connect to the server

Good day all,

Please can you assist, I have setup my SSRS Subscription but keep on getting the same error message:
Failure sending mail: The transport failed to connect to the server

I have check everything I can think of and googled for the last 5 hours.
I'm able to send a test email from SQL "Database Mail"
I have checked port 25 by using Telnet and the port is definitely not blocked.
I have checked and recheck the RSreportserver.config and everything is correct.

Any ideas would be helpful,

Thanks

Never mind got it working.