I just checked your email and it works with our test devices. Have you tried activating it with another internet connection to rule out yours as a source for error? The only possible issue we have encountered would be fixed with these steps:
Make sure your Max2Play device is connected to the internet.
Delete the license in the Max2Play interface and click „save“ with a blank field.
Click on „Settings/Reboot“ again, reenter your license and click „save“.
Check if the green „Activated“ field appears. If not, contact us again for further help.