Tried to read OBD data, now flashes errors that won't go away

Just plugged in a brand new OBDLink LX dongle to see what I can read with the OBDLink software or Torque, but the dash immediately started alternate flashing of "check brake system" and "check charging system". So I turned the key off and removed the dongle, but now those red flashing screens still happen when I turn the key back on.

How can a read-only device cause errors? I checked the dongle connector and didn't see any solder or cross-connections or anything out of the ordinary. I have not tried to start or drive the truck yet. Is there a way to reset the system...perhaps disconnect the battery and wait a few minutes, or a secret reset button somewhere?

I have a support ticket in with OBDLink so will see what they say. I bet it will work just fine on my 2005 Kia but a 2019 Taco seems to have some...oddities...

EDIT: well I went out and started the truck and pulled it out of the garage and the flashing error screens seem to have gone away and everything appears to be normal. On a whim I plugged the dongle back in and now it works perfectly, no errors and no red flashing screens. Wonder if the truck needed to be running instead of just having the ignition on? Oh well, one of life's mysteries, like women...