This is now officially on Bungie's list of known issues. Here's what they've posted so far, from the [url=https://www.bungie.net/en/Explore/Detail/News/49853]TWAB that went up yesterday[/url]: [quote]ARTIFACT PICKUP We are currently investigating an issue causing players who acquired the Seasonal Artifact before completing the full New Light Tower introduction to be blocked from progressing in the Season of the Hunt story and missions. New Light players should be sure to complete the full Tower introduction prior to picking up the Seasonal Artifact from Zavala’s office. We are continuing to monitor for reports of veteran players encountering this issue. If you believe you've been impacted by this issue and are not a New Light player, please report to the #Help forum. [/quote] On the off chance that you have any objectives left over from the New Light quest, try completing those, and see if that helps. If not, unfortunately there's not much else to do but hope they're able to fix the issue soon.