Wifi no longer connecting on oiginal Moto X

A

AC Question

Hello all
My girlfriend has the original Moto X (2013) which she bought last year during a sale on the Motorola website. it's been a good phone for the last year and she hasn't had any issues. That is; until recently when the phone stopped connecting to WiFi. We've tried everything- Disabling mac filtering (wasn't on to begin with), resetting the WIFI router etc. Nothing seems to work. Today there was a system update and the phone seemed to go back to connecting just fine...then suddenly, it stated acting up again. We're both getting extremely frustrated. Any thoughts?