I put my Switch 2 in teh travel dock, the screen on the console turns off like it's supposed to, and then my new 4K TV shows this:

No Signal
HDMI 2
Check the cable connection and the input source.
the console works perfectly in handheld mode. ive tried another HDMI port. im using the cables that were already connected. my kids are waiting to play on teh big screen, and Im completely stuck.
Id rather not buy a new dock if its something simple. If theres a reset or a specific order to plug things in, pls let me know.