@Tholius1 So one error, I did have the 5G on for the main network. I swapped the 901ND for an 801ND and it made no difference. Then, when looking at the A7 settings, I noticed that it had a "feature"...

Archer A7 with the November 2020 firmware. Attached to a cable modem (motorola) with Cox service, both main and guest networks active. 5G and 2.4 only on the main network, 2.4 only on the guest...

The D2 was in service for many years before it croaked in this manner and we replaced it with the 3200. They were both powered similarly via a UPS with surge protection. There was not a power loss...

Both an Archer D2 (no longer made) and my recent Archer C3200 have an issue. At some point, for unknown reasons, they reset to defaults. When I get them re-configured, they work but the web pages on...