Natural Explorer states that:
Your group can’t become lost except by magical means.
If the ranger can't get lost, what happens if she fails her Wisdom (Survival) check to follow tracks?
I think it would be safe to assume that, even though the ranger knows where he/she is, they no longer know which direction their quarry went!
The consequences of this depend on the DM and the adventure.
Either the ranger and other characters need to find another way of figuring out where to go, or it may be acceptable to start a wide search of the area (gradually spiralling out from the current location for example) and making further Wisdom(Survival) checks every so often - say every hour - in order to pick up the tracks again, with the main consequence being time lost.
I agree with another answer, but I have an alternative suggestion too: do not forget that, as DM, you can always replace a failure to do an action with a success with penalty. If you really intended for a character to do some action and his unlikely failure hinders whole plot, allow the action to be completed. Apply penalties instead. Clumsy acrobat did climb the wall. He just hurt himself and attracted guards' attention. Inept tracker did follow the trail, she just took an unnecessary detour into a known owlbear lair. And so on.