Show my caller ID- Won't load

If above doesn't work, try this: turn off wifi and then turn on aeroplane mode for a few seconds then turn wifi back on and aeroplane mode off. At least that worked for me a while back.

Hi, I had this trouble on 2 iphones (X and 7) and they were on two different carriers. This issue is nothing to do with the carriers but simply a delay/underlying structural issue with Apple. Shutting down and re-starting did not work. But then I just turned the Mobile Data slider (in Settings) and back on again and both phones gave me the Caller Id slider again. Can't guarantee this will work for you but if its this easy then this will be a great resolve as it has been an issue for years (see internet questions since 2018) and Apple has not rectified.

There is a scenario and I can't recall which comes first, but you need to turn off wifi, then turn on aeroplane mode.

Caller ID is a carrier feature, what did they say when you asked them?