Yeah this happens quite often, due to whatever reasons
If a reloadui does not work, and a logout and login again does neither work, you often are forced to quit the whole quest row and redo some parts...
I alway search the web and official ESO forums for solutions first, and UESP as well as it often got additional quest infos:
https://en.uesp.net/wiki/Online:Quests
And if you cannot find any help there, ask ingame in the zone chat. At the bitter end you sometimes need to abandon a quest line and redo it from whatever point the game then says you will start again
But it'd always first search the web up and down, ask in guilds. Maybe someone experienced the same or similar.