Hello Ephraim ,
Please first completely remove the AxCrypt app on your tablet. After that, you have to install the AxCrypt app.
We support Andriod v5.o and above.
No limit. You can install and login(with the same Subscription account) to the AxCrypt app with the n number of devices. But If you are the only person is going to use, then you can use it. Otherwise you need to share your account password to all users who are all using the same account. Sometimes this leads to security breach.
still, if you facing any issue, please provide more detailed information about the issue with a screenshot and write a mail to support@axcrypt.net.