AxCrypt will allow the users to decrypt the encrypted file with the original password which is used for encryption.
If the file was encrypted with a different password than your sign in password, then you have to enter the file password while viewing/decrypting the encrypted file. You can open all the encrypted files if you know the file password which was used in the encryption process.
But still your AxCrypt app is sign out mode only.
If you want to encrypt the new file, you need to sign in your AxCrypt account.
So, Please use your latest password(Which password are allowed to log in with your AxCrypt account on the website) to sign in with the AxCrypt app without any issues.
Still, you are facing any issue, please provide more information about the issue and write a mail to firstname.lastname@example.org .