My imei issue has become 00000000000 and I have network issue

Hello

I have an issue in my s8+

My imei has become 00000000000

And I have another issue that my phone dont recive cellular network most of the time but this issue I have it from long time

But the imei issue not from long time

And I thinks the imei issue caused by me after I flashed Germany ROM for my device

I hope you can help me♥️