Let's see, brainstorming from the stupid to the unlikely....

- wrong password

- blocked IP

- supplier forgot to give you admin privileges in the Content Management system access rules

- your caps lock key is on

- your login form requires javascript and you have it disabled.

- aggressive spam protection is filtering you as a bad bot

Assuming you've probably checked your password seven times before posting here, I'd vote for incorrectly set access rules. They think your account has more privileges than it actually does, but you'd think you would be able to log in (though maybe not update).

Time for a new system supplier. Totally unacceptable answer!

"Everything should be fine" isn't a very helpful answer but if it's the truth it's the only answer you want to hear.

Some other steps to take
- Clear cookies
- Clear cache
- Turn off firewall temporarily
- Check your blocked cookies list, sometimes cookies are blocked for you by not so helpful security software.
- Reset the password one more time after all of that.
- Search Bing or Yahoo for stories of other people having the same problem. I'd say search Google but you'll only get a list of "places" these days. :-0

On a hosting services forum I have seen cookie blocking as a common reason for login failure.

Cookie blocking definitely sounds like a good bet.

Did you try a different browser too? Clearing cookies for this domain?

i would clear my cookies, go to the site, see if a cookie appears, login, and then see if the cookie has changed or another one has appeared. if everything is still the same, then you know its a problem at your end.

Thanks for all your replies.

Apparently we had to reset the server. Our i.t guy wasn't in and we are between webdesigners so it was a bit of a mystery.

Yep, I said that wasn't a great reply from the supplier and apparently it was a better reply than the one before used to give!

I'll def remember this thread in case anything happens again, very useful, ta!