Try to un-install and re-install the AxCrypt from your system. After the successfull installation, please restart your system.
Now start the AxCrypt app.
Still if you are facing issues, please write a mail to email@example.com with the detailed information about the issue.
If you can send a screenshot showing where the problem is, it often helps us understand.
How to take a screenshot on your Mac is explained here: https://support.apple.com/en-us/HT201361 .