Stuck on Checking Connection after Factory Reset

A

AC Question

Hey everyone.
I've recently reset my phone (factory reset), and it is constantly stuck on "Checking Connection...". I have found no solution to this online whatsoever, and it is very frustrating. Yes, my Wi-Fi is working well, and it doesn't even work with mobile network.
I am completely clueless, and I really need my phone ASAP.

Thanks beforehand.