This error message is dispalyed on Android devices if you have an own server system and have specified a server URL with https and /ll-master/ in the string.
To fix this, remove the /ll-master/ string from the domain name. This can be done from your MASTER admin system > Settings Tab > Modify Server URL.
This will not affect existing user licenses, so there is no need to re-issue licenses to users apart from those using an Android device who receive this error message. They will need a new license file that contains the updated server URL.