Chosen Solution
The phone fell and it stopped having mobile connection. It does recognizes the SIM and it does have wifi without any problems. The only thing that doesnt work is that, the mobile service. When I try to search manually for networks it says “error when searching for network”. I tried a lot of things like messing with the mobile config or resetting factory settings. The SIM works correctly, I have it in another phone and I have tried another SIM too, but same. I also tried the second SIM slot, but happens exactly the same, it recognizes it but no mobile connection. What could be the problem?
Check if the antenna cable somehow got disconnected, it can happen. Follow this video but only to where the back cover is removed: Redmi Note 4 Only Glass (Touch screen) Replacement
