iPhone keeps asking for password to Apple ID
For the last week or two, my wife's iPhone 6s has kept pestering her to enter her Apple ID password several times a day. She's already tried switching it off and on again, but to no avail. The next thing we want to try is signing out of Apple ID in the settings and then signing in again, but I am worried that this might delete some of my wife's data (which she would most definitely not be happy about). Is that an actual risk, and if so, is there something I can do to make sure she doesn't lose anything? Or, even better, do you know any other solutions I might try?
P.S.: For the last week or two, I've also not been able to see her location in the Messages app, which before was no problem. The map simply isn't there at the top, while I show up just fine on her phone. Is it possible that this is a connected issue, since I believe location services have something to do with iCloud and the frequent login requests might also link to iCloud somehow?
"Nothing is gonna save us forever but a lot of things can save us today." - Night in the Woods