Cant send email form one location, receiving fine

[Greywuff]

I have three accounts in windows mail. I use the computer at 3 locations. At
one location, using my cell phone as a modem, I can receive emails to all
three accts, but get an error when trying to send emaikls. From the other 2
locations, both wirelwss netwirks, it sends and receives just fine. the error
message i get is..An unknown error has occurred. Subject 'test', Account:
'pop.east.???.???', Server: 'smtp.east.???.???', Protocol: SMTP, Server
Response: '421 Cannot connect to SMTP server 68.1.17.4 (68.1.17.4:25),
connect error 10060', Port: 25, Secure(SSL): No, Server Error: 421, Error
Number: 0x800CCC67*
*Server name changed to ???

 

[Gary VanderMolen]

Not sure why you'd want to obscure the fact that the server is
smtp.east.cox.net, since the server identity is often a big part of the
troubleshooting effort. Try this:
Make sure you have send authentication enabled.
Go to Tools, Accounts, select that account, Properties, Servers.
The box for "My server requires authentication" must be checked.