The quest requires you to meet Spider at the Tangled Shore and pay him a bribe as part of your Vanguard Allegiance. After such a long maintenance, I had hoped this would be fixed by now, but it still isn't. I've looked everywhere for a response from Bungie about this but haven't found anything lately.
[quote]• Allegiance Quest: We are investigating an issue where players cannot progress past Spider's Black Market in the Allegiance quest.[/quote]https://www.bungie.net/en/Forums/Post/252323677?sort=0&page=0