I haven't been able to find anything in the router settings to change after researching my router for hours - any ideas? Perhaps there is a bug in the firmware? The problem of not being able to access some websites seems like an MTU issue but I have tried several MTU values from 1492 to 1300 with no success.
MrOriginal1: I've also just found that when the WAN cable is connected while the router is in PPPoE mode, I can also not access the router admin page.
So not only are some web pages unable to load, the router config page cannot either. If I disconnect the WAN, the config page loads instantly.
This is expected. Your router won't be routing out over the WAN port to the local IP address your modem has. I've never been able to get this working (Tho I am told it's possible with a static route - but I can't get it to).