I recently had to test with two laptops with the Android emulator and tried to register with the same Mobile Api Gateway.
The first “device” successfully registered, but he second received a device already registered.
The reason for that is the usage of the IMEI number together with some other fixed gateway number
The IMEI number for the emulator is 000000000000000 which is the same for all emulators and is
not changeable in the emulator or any other configuration file.
A way to circumvent this, is to change the IMEI number inside the emulator-x86.exe with a hexeditor like notepad++
Search for “+CGSN”, the following 000000000000000 is the IMEI number. Change to the desired number and the save the file.