Can't send in Windows Mail, Can in Thunderbird

[LMEL]

I can receive email in Windows Mail, but can no longer send out. This
started about a month or so, give or take. But, the messages aren't stuck in
the outbox - I can delete them. The error message I get is:

An unknown error has occurred. Subject 'Re: Nursery Care for July & August',
Account: 'mail.xxxxxxx.com', Server: 'mail.xxxxxx', Protocol: SMTP, Server
Response: '451 Please try again later.', Port: 25, Secure(SSL): No, Server
Error: 451, Error Number: 0x800CCC6A


I set up the account identically in Thunderbird and have no problems sending
emails. Any thoughts?

 

[Guest]

I can receive email in Windows Mail, but can no longer send out. This
started about a month or so, give or take. But, the messages aren't stuck
in
the outbox - I can delete them. The error message I get is:

An unknown error has occurred. Subject 'Re: Nursery Care for July &
August',
Account: 'mail.xxxxxxx.com', Server: 'mail.xxxxxx', Protocol: SMTP, Server
Response: '451 Please try again later.', Port: 25, Secure(SSL): No, Server
Error: 451, Error Number: 0x800CCC6A


I set up the account identically in Thunderbird and have no problems
sending
emails. Any thoughts?

'mail.xxxxxx' is not a valid server name, so if you haven't munged it,
you'll
have to ask your email provider where to find their setup instructions,
which
should contain the correct server names.

In Windows Mail, unknown errors are often due to interference from an
antivirus program. What if any antivirus programs do you have, and have
you ever had a Norton or McAfee antivirus program on that computer,
even one of the free trial versions that often come already installed on
new computers?