Helldivers 2 matchmaking finds players then fails to start

Helldivers 2 matchmaking searches forever or fails after finding players. Restarting sometimes works, which makes the cause hard to pin down.

How should region, cross-play, party size, firewall, and anti-cheat startup, matchmaking, voice chat, and heavy combat frame drops be tested before assuming the servers are down?

Start with party consistency.

1. Everyone restarts the game and launcher.
2. Confirm matching versions, cross-play settings, region, and privacy.
3. Make the player with the most open NAT the party leader.
4. Remove VPNs and pause background traffic.
5. Test solo queue for every member.
6. Rebuild the party one player at a time.

For Helldivers 2, include anti-cheat startup, matchmaking, voice chat, and heavy combat frame drops. If solo works for all but the full party fails, compare the last player added before reinstalling anything.