I’m out and about right now and my iPhone is acting like it has a very poor (no) cellular signal. I thought it might be due to weather related stuff (aka it’s snowing). At locations where I normally have great cellular data, I have nothing.
So, I ain’t stoopid so I restarted my phone.
Everything is great now, but why?
While I had experience with troubleshooting this sort of thing when I did Tech Support for T-Mobile, we had a lot of arguments about your very question - “Why?”
The answer we came up with, that satisfied most of us, is based around the understanding that a smartphone ISN’T a phone. It’s a computer that has highly advanced supplemental communication suite. So just like any other computer, it occasionally borks a setting. It most likely is somewhere in the ‘carrier settings’ - which is the software which tells your iPhone what carrier you’re using, and what bands (freq) your carrier supports.
If it’s looking at the wrong info, you get poor (or no) connectivity. Restarting gives it a chance to ‘repoint’ as it were. Although with iPhones, I find more frequently you needed to go to the ‘reset network settings’ fix. And while Android phones can have similar issues, iPhones always seemed to have it worse.
eye phones often do stupid things. Mine commonly gives me a “Cannot Verify Server Identity” when I’m in a wifi hot spot log in. Many times I simply have to use my data instead. This apple stuff can be quite crappy, IMHO.
I find sometimes that clicking the phone into “airplane mode” and waiting a few seconds, and then turning airplane mode off will find my connection again.