If you have recently upgraded to Sage50cloud v27 then next time you login, you may get this error message. This has confused a client of mine this week as no one had changed their password, but all of a sudden after the upgrade they could no longer login ...
If you used to have a long password in your Sage then this is an easily fixed problem. In prior versions before Sage50cloud v27, the system allowed you to create a longer password of more than 10 characters, but the system only read the first 10 characters and anything from character 11 onwards was ignored.
This means that if you keep typing your long password it won't be recognised after the 11th character. I didn't find this out for myself at first as my password has always been 9 characters long so it wasn't until a client had this problem that I was aware of this change.
So, the answer is when you first login after upgrading, only type the first 10 digits of your old longer password into Sage50cloud v27 then continue to use this password going forward or go to Settings->Change Password and reset the password to the longer one you thought you had before!
This is perfect as you can now set it up in case you ever forget your password. Sage50cloud passwords are also not case sensitive, so you can use upper or lower case or a combination of the two and still log in.
If anything I've written here resonates with you, call me on 01604 420057 and let's see how we can help you.