Unable to activate iPhone (red triangle exclamation mark)

Hello!

I cannot activate iPhone after reset. It cannot find Wi-Fi networks. I was trying to put in DFU mode and reset via iTunes - iOS installed successfully without errors.

Also I tried with SIM card with 4g network access (NO PIN): on the left corner i had “4g”, and still stuck!

On the “Hello” screen “i” button shows IMEI. What might be wrong with this iPhone and what would be the solution?

Thanks!