Missions in VALORANT typically reset on a regular schedule set by Riot Games. If your missions haven't reset despite the timer showing 0, there could be a delay or a temporary bug. Try restarting the VALORANT client to see if it helps. If it still doesn't reset, you might need to wait a little longer as it could be a server-side issue. For persistent issues, check the Riot Games Support page for any announcements or file a support ticket for assistance.