I am using 4 TL-WPA4220 extenders to create WiFi in the house (3 floors and garden) and a TL-PA4010 to feed the signal to the grid, located very close to the router. Since approximately 6 weeks I experience random loss of WiFi (once or twice a day). (Could be coincidence, but this was at the same moment that my solar panels were switched off because the system was expanded).

Since the router kept functioning OK I concluded that this must be due to my powerline system, so I bought a new box with 1 extender TLWPA4220 and 1 TL-PA4010. To my big surprise this did not lead to an improvement. I called my telecom provider to check the router, they checked but couldn't find a failure. I changed the cable connecting the router to the TL-PA4010, no change.  

Usually I reset the router to get WiFi back, but yesterday when the WiFi was down and I unplugged the ethernet cable from the TL-PA4010 to the router and reconnected it, and the WiFi was back, so I got the feeling that it must be due to the powerline system despite the fact that it is new.

Worth mentioning: the system worked flawlessly for almost 2 years. The house dates from July 2020 and has a 3 phase grid.

Hardware versions of the extenders are 4.0 and 5.0; the TL-PA4010 is 3.0

Hope you can help out!