Norton Antivirus causes email sending problems
The outgoing email scanning function in Norton Antivirus is usually turned on by default. Individuals who use NAV should be aware that the scan does not support SSL. Please do not be alarmed if the following message occurs:
Unable to establish a SSL connection with the server. Account: ‘SSCNET’, Server: ‘mail.ucla.edu’, Protocol: SMTP, Server Response: ‘454 TLS not available due to temporary reason’, Port: 25, Secure(SSL): Yes, Server Error: 454, Error Number: 0×800CCC7F.
Simply turn off the outbound scanning feature and the email client using SSL can send mail again. See NAV help files to disable scanning feature (instructions will vary based on different versions).
UCLA pays for Sophos, so that is what I use. However, Notre Dame uses Norton, so here are some instructions from its site: