Outlook suddenly won't send

Sp00n · 4 Aug 2010 at 11:40

Have a problem this morning whereby outlook will receive emails just as it always has but refuses to send, coming up with the error:

"(0x800CCC80) None of the authentication methods supported by this client are supported by your server."

Now I've been searching around and everyone is saying turn off authentication blahblahblah which isn't a fix because:

a) no settings have been changed and it has been working for many months as it is.
b) server doesn't allow relaying so it will fail with a different message
c) exactly the same settings work fine on another pc

It's not the server as I have set the account up on another pc with the exact same settings and it works fine, it's definitely something to do with the outlook itself because setting up a different account on the problem pc causes the same error message, the only thing I haven't tried yet is to set it up under a different logged on user to see if its profile dependent.

I know 2007 does some strange stuff in relation to the authentication but re-creating accounts/profiles doesn't seem to make any difference.

For the record, the server is pop3 running sendmail.

I have had this on one other pc temporarily and the user sets up a different smtp server and everything is fine, so its got to be something to do with the way outlook authenticates against sendmail but I just don't know enough.

SiriusB · 4 Aug 2010 at 11:45

The last time I came across this I resorted to reinstalling Outlook!

Sp00n · 4 Aug 2010 at 13:01

Really? Grrr, I suppose I could try that, it'll at least save the mapi profiles but it's just annoying that it happens and there is NO reason for it :\

SiriusB · 4 Aug 2010 at 14:33

There may be a solution, but I have found with Office it is usually quicker to try reinstalling it before spending hours searching for solutions.

theheyes · 4 Aug 2010 at 15:55

Hmm, does the server have any rules for accepting only certain hosts on the network?

Dano · 4 Aug 2010 at 15:55

Last time I saw this it was due to a change on the server and capitalisation on the email account ie; [email protected] would generate the error but [email protected] would work just fine.

Sp00n · 4 Aug 2010 at 16:11

Nothing has changed, works one day, doesn't work the next.

Dano · 4 Aug 2010 at 18:55

Sp00n said:
Nothing has changed, works one day, doesn't work the next.

Nothing your end has changed. Liek I said, it was a server change that caused the issue on the machine I saw.

SiriusB · 4 Aug 2010 at 23:12

What would change on the server that would affect only that particular computer? As Sp00n has said, Outlook with his account works fine on a different machine and any account on his machine fails.

Dano · 5 Aug 2010 at 02:05

SiriusB said:
What would change on the server that would affect only that particular computer? As Sp00n has said, Outlook with his account works fine on a different machine and any account on his machine fails.

I've no idea, all I know is that it did cause a very similar issue that I have seen before and due to a typo when inputting the username a capital letter was used, the account worked perfectly on both machines for months and out of the blue the one with the capitalised account name got rejected with the same error Sp00n is seeing, removing the capital fixed it instantly and as it is such an easy type to make and not see it's worth double checking.

Sp00n · 5 Aug 2010 at 09:22

Reinstalled office and still getting the same error, new profile, same error.

ended up setting up the user on a new computer all together and it works fine on there so its definitely something computer/office related.

Every answer I can find just says turn off SMTP authentication which is irritating because my server requires smtp auth.