I just noticed emails sent using a contact form in wordpress wasn't delivering and then I checked the mail log and found the following error:
Authorization failed (535 Authentication failed: Bad username / password)
This site has been in production for a few years now and this has always worked but all of a sudden I just noticed it isn't working anymore.
I tried running a script with just the mail() function to see if it was a problem with my wordpress installation or the plugin used but I got the same error.
Thanks in advance.
