I have discovered that my iPhone would not connect to my home network when I would arrive back home. I had to select it and enter the password each time.

Even after switching my SSID to the same name on 2.4 and 5. Then back to being separate. My iPhone still had connection problems. Both my Mac and iPad would stay connected, there again they never left the house.

I even signed out of Apple ID on everything and what not. Went weeks doing this and kept on denying it was the router as everything else worked.

Finally I rebooted the router for a few minutes and it's been working for over a month since then. I guess when changing the SSIDs that it did not do a full reboot or something.

KOT