I recommend trying a factory reset and set up from scratch. Save a router config to file before doing the reset. Just in case.
Disable WPS and set IPv6 to Local Connection Only.
- Check cable between Modem and Router, swap out to be sure. Link> Cat6 is recommended.
- Any other WiFi routers in the area that maybe causing interferences? Link> Use a WiFi Scanner to find out. How many?
What web page issues are you referring too?
If you seeing this on both routers, possible problem with ISP service/modem. I recommend that you have your ISP check the cabling going to the ISP modem, check signal levels going to the ISP modem. For DSL or Fiber service lines, ensure that the ISP is using good working phone or cable lines to the DSL modem and that the phone lines are filtered correctly. For cable Internet,
RG-6 coaxial cable is needed, not
RG-59. Check for t.v. line splitters and remove them as they can introduce noise on the line and lower the signal going to the ISP modem. I recommend having the ISP service physically check the lines going from the out side to the ISP modem. Connecting to the ISP modem could result in a false positive as the signal to the modem could be just enough to that point then adding on a router, could see problems.
The router operation is dependent upon getting good data flow from the ISP modem and the modem is dependent upon getting good signal from the ISP Service.