@ArcherC8 192.168.0.1. It does work on my wireless laptop and DID work on my wired MAC. But I literally need to reset the router and restart everything for it to work on the wired connection... for a day. 

Yes, reset router and modem and computer.

@HPCBOB Have NOT tried it with only the PC connected and the other Ethernet ports empty and nothing in the USB ports? (USB port is empty regardless.

It is working at the moment. I should add this apears to be intermittient so will need to wait till next incident and try that.

Also, instead of the log in screen of inactivity, it will frequently ask to set up a new password. Doing so, it returns that I can't because i have already done so. 

Many many many refreshes later i can get back tot log in screen that freezes.

Note, this is a brand new, out of the box router and it is doing the exact same behavior of the prior that I returned. 

I'll try isolating ports as a diagnostic but that is not a practical long term solution for a new rather expensive router!

@HPCBOB NEw information is that if safari is restarted the problem persists.

But if i restart the computer, it seems to temporarily work. Again, not a viable option.

Virus protection on or off doesnt seem to matter.

It's a imac running Big Sur but did the same with Catalina.

any ideas?

@ArcherC8 Thanks. But should note that even with default router settings, the issue persists. I'm willing to blame the imac but do not now where i would go to change some setting that appears to simply change with time. Being that it does work after a computer restart, i need to wait some "random" time befiore it doesn't work again. All I can say at this point is I restart, it works, i go about my work, retry some time later (hours perhaps) then locked. I also thought maybe i needed to actually log out (vs time out) but that did not seem to make a difference.