Maintenance for the week of November 18:
• PC/Mac: No maintenance – November 18
• ESO Store and Account System for maintenance – November 19, 9:00AM EST (14:00 UTC) - 6:00PM EST (23:00 UTC)
• PlayStation®: EU megaserver for maintenance – November 19, 23:00 UTC (6:00PM EST) - November 20, 17:00 UTC (12:00PM EST) https://forums.elderscrollsonline.com/en/discussion/668861
The compass marker won't show sometimes if there is a hill or other land feature between you and the object. It's also possible that you're just missing the marker, and that it is really there; I once ran around for an hour looking for something that wasn't at ground or eye level, but hanging by a hook 8 feet in the air. Look for "(above)" and "(below)" indicating that you're not on the same level as what you're looking for--you won't see it until you're on the same level, well, much of the time. There are exceptions.
It's also possible that there's an interaction bug, in which case leaving the immediate quest area, logging out, then logging back in 30 minutes later, might help. Be sure you've also read the quest text in your quest journal, so that you're on the quest step that you think you are.
I know those are just general ideas, but I hope one of them will help.