No sim Error on iPhone 14 Pro Max

It still sounds like a carrier issue. But you can try resetting your network settings.

Reset your network settings



If you're using iOS or iPadOS 15 or later, tap Settings > General > Transfer or Reset [Device] > Reset > Reset Network Settings.

If you're using iOS or iPadOS 14 or earlier, tap Settings > General > Reset > Reset Network Settings.

This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

Are you using both eSIM and SIM or just one? If the physical SIM card is failing, visit your provider for a replacement card. The eSIM may need to be reprovisioned by your carrier. Carriers can reprovision the eSIM over the air, but in my experience, doesn’t work all the time. A visit tp your carrier service center may be the best course of action.