Please explain what kind of file type do you encrypt? Are you getting any exceptions or error messages while using the AxCrypt app? If yes, what type of exception or error message you are getting? Please share the details of that exception or error message. If you can send a screenshot showing where the problem is, it often helps us understand.
AxCrypt can encrypt most of the file types. Also some file types AxCrypt will not encrypt due to security reasons.
AxCrypt will not encrypt any system, hidden files and operating system installed drives/folder. So please avoid securing that kind of folders.