Iphone unavailable try again in 8 hours

Hi guys, i'm totally new on this and I'm asking for your help.

I got an iPhone Xr and recently I wanted to restore it but from now on, he is stuck on saying "iPhone Unavailable, try again in 8 hours". After waiting for 8 hours, the iPhone is on the retrieval data mode.

When restarting it or attempting a restoration by DFU Mode or Recovery mode, it reboots and says again "iPhone Unavailable".

I tried many things and I'm always back at the beginning. So if you have an idea please tell me.

Thank you for reading !