Put the pin into the switch test and manually press on the switch. It could just need adjusting the lever to make the ball push on it more. If you push it all the way by hand and it still does not register then replace the switch. If it registers when pressing by hand then bend the lever so that when the ball rolls over it, it will push on the switch more.

You may need to take the POTD off the game to adjust the switch.

I actually just had to do this on my LOTR the other day. It was the top right in my case; it wasn't consistently registering roll overs. I verified by doing a switch test the switch was OK & simply needed to be more sensitive (above field lever higher in my case.) I was able to carefully bend the above field tab a teeny bit without removing the POTD & make the switch more sensitive. It works everytime now! My understanding is that this is pretty common with switches in general over time.

Again same with my LOTR, 1 POTD switch not working. Oddly worked in switch test but never during actual gameplay despite adjustment. In the end the switch needed to be replaced, new one works great.

PN is 180-5057-00, looks like its a Cherry DB3 its cheaper to buy the switches without the actuator instead of as an assembly, not positive, but its very likely that every microswitch in that game is a DB3

http://www.pinballlife.com/index.php?p=catalog&mode=search&search_in=all&search_str=180-5057-00

it is a 180-5057-00

http://www.pinballlife.com/index.php?p=product&id=2045

My upper right POTD switch has started to fail when playing, but always tests fine. Probably wearing out. Adding one to the cart for my next order.