a few days ago I got a Job Service Android Samsung J4 SM-J400G which was constrained not being able to use Phone, SMS, and Internet because when the SIM card was installed a notification appeared Only Emergency Calls and Cellphones Not Allowed. 
after I dug up information from the owner and based on the inspection results, it turned out that the J4 SM-J400G was a foreign product originating from Thailand. No wonder the Samsung J4 SM-J400G cannot be used in Indonesia because it has been confirmed that the IMEI is not registered.
to fix the problem of Samsung J4 SM-J400G that cannot be used Phone, SMS, and Internet because it can only make emergency calls because of an unregistered IMEI (overseas cellphone) the way is to Root first then repair EMEI (change IMEI) using the Samsung Tool Pro application.
How to Install TWRP Samsung J4 SM-J400G
To Install Custom TWRP Official Samsung J4 SM-J400G all you need is the ODIN application, File TWRP Samsung J4 SM-J400G, and File no-verity-opt-encrypt-6.1.ziprun the ODIN application, then connect the Samsung with USB in Download mode, press and hold simultaneously the Volume UP, Home, and Power buttons, after the Samsung Logo appears, release the Power button and keep holding it and press the Home and Volume UP buttons until it enters mode download.
Remove the Auto Reboot Checklist then click Start to start the TWRP Install process
After the flash is finished, just test, try turning on the Samsung J4 SM-J400G by pressing the Volume Up and Power buttons together, and Alhamdulillah it worked.
Check and make sure whether the Samsung J4 SM-J400G Internal Memory is read or not.
If the Samsung J4 SM-J400G Internal Storage is not readable (0MB) do Wipe Format Data and Restart back to Recovery.
After Wipe Format Data, the Samsung J4 SM-J400G Internal Storage will be read marked by the emergence of Internal Storage capacity.
Next step Install no-verity-opt-encrypt so that later Samsung J4 SM-J400G does not Bootloop when restarted to System.
That's the Tutorial Guide How to Easily Install Custom TWRP Official Samsung J4 SM-J400G that you can try to practice. Read Next Article Easy way to Root Samsung J4 SM-J400G Magisk