I have a Dell Precision 5530 on a WD19TB dock that is no longer charging through the dock. The only way it charges is if I plug A/C adapter in, then connect dock for it to display on external monitor. If dock is plugged in first, then A/C, it also does not charge. The laptop battery slowly dies.

Dock is working as I have another Dell laptop that works on the same dock and setup fine through Thunderbolt cable.

Any ideas? All firmware is up to date and everything else works fine. I first noticed it when in a game and graphics got choppy when there was a lot of stuff going on. Checked power/battery and noticed it was not charging.