I’ve been able to get a dungeon within a reasonable time for all of my characters -except- for my warrior tank. For the past few days, I’ve let it get up to a half hour before I quit and do something else.
Which dungeon finder are you using. A Chromie Time expansion one? The War Within Normal or heroic? Timewalking?
What time were you trying to do dungeons? If you’re queing at very different times with different characters that could lower the dungeon pop time.
You for sure have Tank selected as your role in your warrior?