Lb112x and ASUS router - worked, then quit

Have had a NetGear LB1121 running and connected in MoHo for almost a year without issues. Used it the first weekend in April, no problem. Went to use it the following weekend and it won’t connect.

Just this weekend I was able to do some testing -

Connecting the LB1121 direct to my laptop using the Ethernet cable, everything works fine.

Disconnecting the LB1121 and powering up the ASUS router, the laptop connects via wireless to the ASUS router without issue.

When I plug the LB1121 into the ASUS and then try to reach the Web, I get nothing.

ISP is AT&T and LB1121 is on a data plan.

Strange as nothing has changed on my end, I’m suspecting AT&T has changed something on their end but not sure how to locate the issue (and not sure AT&T front line can really lead me to a solution).

As of last night, firmware was up to date per the LB1121’s firmware check Option.

Anyone have any ideas what to check? Confusing as it worked flawlessly for a fairly long time.

TIA!