Friend consistantly can't join

[King Super Lube]

We've had this issue for a few days now. My friend isn't able to join us. We've tried almost everything out there when it comes to troubleshooting. He's still unable to join.

List of things we've tried:
- Turning the PC on and off again.
- Quitting and opening steam.
- Reinstalling the game.
- Tried on WiFi and Ethernet.
- Enabling and Disabling Cross Play.
- Generating Friend Code with Cross Play.
- Deleting system cache.
- He goes into quick play then tries to join.
- He goes solo then tries SOS beacon.
- As a group we go solo and try SOS beacon.
- Adding edge traversal to firewall.
- Disabling firewall.
- Tried every combination of joining friends 4 different friends.
- Set matchmaking to public and friends only

Things we've attempted:
- Updating DNS server. This wouldn't stick. His computer refuses to keep a connection with any DNS other than his ISPs.

Things we haven't tried that I've seen in other forms:
- Installing on Steamdeck. Luckily he has one so we'll try this one out and report back some time tomorrow.
- VPN into your state to force the game to choose the correct servers. I saw this was an issue for starlink users. He doesn't have starlink, but it could be an issue. We'll likely try this after Steamdeck.

This is a lot of work to go through to get this game to work. Please fix.

Edit: Some background info - we're a team of 4. Only this one friend has this issue. His GPU is a 3060. He never appeared as on Ship. Always online or in main menu.
Edit: Installing on Steamdeck fixed the issue. He now appears as on Ship and we're able to accept each others invites.

[GatoMancer]

My Dive team mates found that having the session set to "friends only" sometimes will still block friends from joining claiming it's "Private", Try setting the session to Public while you're on the Ships and attempt to join up. If that works the host can set it back to Friends only and it should be fine.

[King Super Lube]

Originally posted by GatoMancer:

My Dive team mates found that having the session set to "friends only" sometimes will still block friends from joining claiming it's "Private", Try setting the session to Public while you're on the Ships and attempt to join up. If that works the host can set it back to Friends only and it should be fine.

Thanks for the reply. We've tried this as well. I'll make sure to add it to the list of things we've tried.

[Just an Ant]

Good to know im not the only one having this issue, sucks i cant find a fix i can do

[LupisIgnis]

Seeing same issue. Have no clue how to fix.

[Lovyan]

One thing isn't on the OPs lists which is worth trying, which also might be an issue for others here that haven't got it sorted: verify your game files before starting the game, every time you want to play.

I'm in a similar situation to the OP: I'm one of a 4-person dedicated team who plays almost every night, but as soon as the latest update rolled in, we started having major issues with trying to log in, seeing the correct player data, and all sorts of other fun bugginess. I'd had issues before (which enabling crossplay fixed, even though I don't actually need it), but not like this.

As it turned out, we eventually realised that - as long as we verify the game files before starting the game - we could log in and play as normal. This is because Arrowhead have borked something that apparently 'corrupts' one (1) file which always needs to be reacquired.

Try that, and if it works, great. If not, I'm at a loss.