Hardware version re650: V2

Firmware Version re650: 1.0.5 Build 20211130 Rel. 77836

I have had consistent problems with my oc trying to connect to the internet through my extender. It will take 10-15 minutes to connect to the internet and stay connected but today it has not been able to connect at all. It keeps saying "Cant reach the DHCP server. The network connection quality might be low." And sometimes it would say "no internet connection - connected locally only". I don't understand whats wrong because I've used the extender since last year august and ive only had problems start last month and it keeps getting worse. I've deduced that it is not my PC ethernet port's problem nor is it my ethernet cable. My phones connect to the 5Ghz band just fine and I get the wifi speeds that are expected. I also acquired an RE650 yesterday which worked straight away and my pc connected immediately but it quickly got the same problem as my RE500x and refuses to connect to the internet. I dont have access to the router as i live in the flat and i recently called the isp to change the extender they use.