Your problem has nothing to do with the versions of AxCrypt installed. It has to do with the fact that you (probably inadvertently) used a different or mistyped a password for the files you encrypted in June 2016.
Since you’re signed in with a password, and that does not work for these files, AxCrypt will ask for the file password. When you then enter the same password that you’re already signed in with, that won’t help and that’s what the message is for.
You need to remember what password you used in June 2016.
This is one of the reasons we’ve changed AxCrypt 2 to use a single, verified, password – to minimize the risk of this situation happening.