Advice to fix my mother's Galaxy S4 Google Authentication Error + Poor Performance
Ok, so my mom's s4 runs pretty poorly because she has had some kind of Google Authentication error for a long time and just tried to fix it (she has 59 updates pending). She needed it to navigate her somewhere and Google Maps didn't seem to be working (presumably because it is out of date?) so I tried to side-load the Waze APK and that download failed for some reason. After she changed her google account password to authenticate the account and I tried to update maps and it first said "Download Pending" and then it went back to saying there was an authentication error.
Unfortunately I do not have the phone with me at the moment so I am not sure what version of Android it is running (certainly not lollipop because it not the same as my S6 running 5.1.1) and it is not rooted or anything, but I have never encountered this problem on my S6 or my old S4.
Second question, she has never cleared the cache on her phone before and I have been thinking about doing it for her, but will clearing the cache for the first time on a 2+ year phone on its last legs have any negative effects? Any other advice short of a factory reset to get the phone running faster would be greatly appreciated!!