This issue can be caused by corrupted cookies or cookies that are blocked.

• check the permissions on the about:permissions page and in "Tools > Page Info > Permissions"
• https://support.mozilla.org/kb/fix-login-issues-on-websites-require-passwords

Clear the cache and remove cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

Thanks, but that didn't help !

I have cleared the Cache as instructed, and cleared the Cookie for this site ( again ), but the problem is still the same.

The stored Password is obviously correct, as the second attempt works - without changing anything in the pre-flled Username and password fields, and just clicking the "Submit" button a second time.

I only get the "Incorrect password" message at the first attempt to Log on after opening Firefox. If I log off and leave Firefox running then Log back on again, I log on successfully, but if i shut down Firefox then re-open it and try to log on, I get the error again !

Could it be anything to do with the actual site I am accessing - as I don't have this problem on any other site I visit that also requires a Username and Password ?

Thanks.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

OK,

I just tried that and if I start Firefox in Safe Mode the problem does not occur, and I can Log In to the site successfully first time.

If I close Firefox and restart "Normally" then the probem is still there, so I'm assuming this is something to do with one of the "Add Ons" that are disabled in Safe Mode ?

Now I just need to work out which one !

Good luck. And let us know what happens.

Can you post a list of your extensions?

• https://support.mozilla.org/kb/Using+the+Troubleshooting+Information+page

If you use extensions (Firefox/Tools > Add-ons > Extensions) that can block content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then make sure that such extensions aren't blocking content.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Thanks for the suggestions - I have now sorted the problem out, which wasn't related to Add-Ons or Extensions at all !

I had the Web Site Log On page saved as a Bookmark on the Toolbar, and after changing my Password at the Web Site, despite manually logging on and asking Forefox to remember / update the new Password, it seems that the old Password was still saved with the Bookmark, so the first attempt to log on using the Bookmarked page immediately after Firefox had been started, used the old password and gave the "Incorrect Password" message, but then the second attempt to Log On used the "Saved" Password.

After deleting the Bookmark, then Logging on manually and re-creating the Bookmark, everything works as it should again, with no more "Incorrect Password" messages.  :-)

Well, that's a new one.

That was very good work. Well Done.

Best is to avoid bookmarking a specific page that was reached by sending POST data in a (hidden) form or bookmarking a page that has GET data appended to the URL (?xxx=xxx) or links to a specific domain in case load balancing is used as they can easily get broken if changes are made on the server.