I had the same problem. iPhone 16 pro max, IOS 18. After the transfer from old phone to new one Reolink app would not connect to NVR.
Here is what solved the issue: go to settings->Apps->Reolink. Turn off and then on "Local Network". Then restart iPhone.

I had the same problem. iPhone 16 pro max, IOS 18. After the transfer from old phone to new one Reolink app would not connect to NVR.
Here is what solved the issue: go to settings->Apps->Reolink. Turn off and then on "Local Network". Then restart iPhone.