I have a GFCI that does not trip with the plug tester. I tried troubleshooting the issue. I looked in a junction box, and found all the neutral wires coming from the subpanel were all connected at the junction box.
Should I disconnect that neutral from the rest, so that the outlets have a separate neutral? When I try tripping the GFCI with the tester, the neutral light only on the tester goes out but does not trip the GFCI. Also I tried to short the outlet out by touching ground to neutral, and the 15 amp breaker did not trip.