R6300 Incorrect Password

I have had the R6300 Router for about 3 years with ZERO problems. About 18 months ago I hooked up an LG OLED 55*PUA flat screen to my network using the Netgear R6300. It has run perfectly until 24 hours ago when I lost the connection to the TV about 8:30PM. . I thought the cable had gone out and waited until the next morning to check. My PC and laptop are working fine but the LG TV says it can't connect because I'm using the wrong password for the network (NetGear52). It finds the network but when I input the factory password it says it's the wrong one?? Today I downloaded the Netgear Nighthawk app on my phone. It instanly found my Network (Netgear52) but couldn't connect. Said the password was wrong. I manually entered the the same password (printed on the Netgear Router and never has never been changed. It said I had the wrong password!! I shut everything down and did a reset on the router but nothing has worked. I'm an old guy and haven't messed with this stuff too much so I'm at a loss on how to fix the problem. All my other wireless stuff is working fine, just the LG TV is out and I'm at a loss. Any suggestions on how to solve this??