Help 2011 Itasca Cambria 30C

Check that the coach/house battery switch is "enabled" (coach batteries are "enabled"). Usually near/in the stepwell, near the side entry door.
If not, consult the Owner Manual if you have one, or go to the manufacturer's website and download.

Check fuses in the 12-volt power distribution panel. Often located behind metal plate adjacent to the 120-volt circuit breakers.
Some panels have fuse behind the display.
Winnebago/Itasca has manuals and drawings on website. Winnebago

My 09 Cambria had some fuses in the storage area closest to the door on the outside of the coach. . There was a carpeted panel that was removable and they were behind there. Can't remember what they serviced.
Also there was a GFI at the sink area that was part of the inverter hook up. It tripped a few times and caused some interesting loss of power in the coach.
I have had issues that were power related and to find wiring that did not make any sense why this was connected to that was not uncommon.
Remove that panel and trace some wires. i was second owner and original owner added a switch eliminating that panel to start the generator. You may have power but the panel is toast.