The 3 things that have changed recently are 1. I reset my Airport router due to network outage issues and 2. I upgraded to OS Catalina.
I tried enabling the Timed Access control and added my printer MAC address. That did not work as well.
If you reset the AirPort router, then in effect you have a "new" router that the printer may or may not recognize.....even if you used the exact same names, security and password for the AirPort. That is why you would need to reset the printer back to its factory defaults and then set it up again.
"Updating" to Catalina could also possibly cause an issue with the printer if HP has released updates for newer operating systems. Check to make sure that you have the latest printer drivers from HP.
Please do not try to "enable" the printer using Timed Access, this only make things more complicated. Later, once you have the printer working again you could set up a "rule" in Timed Access to only allow users to print during given hours each day, but most users don't want to fool with something like this.
Timed Access is really designed to keep Junior's iPad off of the Internet in the middle of the night.
For now, please delete any settings that you might have set up for the printer in Timed Access.
There is an old saying among network guys..........Change one thing on the network and everything on the network will change.