If this is your first time seeing this error, please try that activity again and resume what you were doing before encountering the error. If you encounter this a second time, please exit Destiny then relaunch the game.
If you repeatedly encounter this error, it likely means were testing something on our servers. Check out help.bungie.net and follow @BungieHelp for updates. If we are not currently running any publicized tests, please troubleshoot your connection by following the suggestions on our Networking Guide.
If you continue to encounter this error for an extended period of time, one final option to attempt a fix is to delete Destiny on your console and then reinstall Destiny.