What are you when the screen shows the "Mission Complete!" is displayed? Have you let the mission ends in xx seconds count down to zero and let that take you back to the Dreaming City?
Hi there. You may want to perform a [url=https://www.bungie.net/en/Help/Article/46501]scan and repair[/url] in the Battle.net app to see if that may help with your issue, then try again. If that doesn't work, delete the following local cache/settings directories found in Windows Explorer: [quote][b]%APPDATA%\Bungie\DestinyPC[/b] [i]*WARNING* Deleting these will cause you to lose persisted settings, such as logged in users, keybinds and graphics settings in Destiny 2.[/i][/quote]