An unknown error has occurred.

Server: 'smtp.iprimus.com.au'
Windows Live Mail Error ID: 0x8007007A
Protocol: SMTP
Port: 25
Secure(SSL): No

Cannot find any solutions, receive emails ok just cannot SEND, have been onto my service provider to check all is ok they suggest m'soft. 2 days wasted so far would love to go back to 8.1 but not game to do so. This problem appears to have been ongoing for years, SHAME.