Hi @annah44 ,
Things to try without resorting to a factory reset.
Try clearing the phone’s cache partition and check if this resolves the problem.
DO NOT select wipe data/factory reset as this will erase all your data and downloaded apps and reinstall the operating system.
Try starting the phone in safe mode and see if the stops boot looping.
If it does then a downloaded app is the cause of the problem. The trick is to find out which one is the culprit.
You will need to uninstall each downloaded app, one by one and test the phone in normal mode between each uninstall to check if the problem is still there or not. When it is OK then the last downloaded app that was uninstalled was the cause of the problem.