A FiveM client that hangs on "connecting" or fails the handshake usually points to the server's ports, a heavy resource at startup, or a client cache problem. Here's how to narrow it down, including txAdmin and artifact-version causes.
Quick answer
Stuck on "connecting" or a failed handshake usually means UDP port 30120 is blocked while TCP is open, so players can see the server but never finish joining. Open 30120 for both TCP and UDP, then look for a heavy resource stalling startup or an outdated server artifact, and clear the client's FiveM cache.
"Stuck on connecting", a failed handshake and "o:err" all have the same short list of causes. The fastest way to solve it is to work out whether the problem is on the server (affects everyone) or the client (affects one player) and go straight to that fix:
| Symptom | Likely side | First thing to check |
|---|---|---|
| Everyone stuck on connecting | Server | UDP port 30120 open? A resource hanging the join? |
| One player stuck, others fine | Client | Clear that player's FiveM cache |
| "o:err" on join | Client | Corrupted cache — delete and relaunch |
| Reaches list but handshake fails | Server | UDP half of 30120 is blocked |
| Was fine, broke after an update | Server | Server artifact version vs client mismatch |
Server side: ports & the handshake
FiveM uses TCP and UDP on the same port (default 30120). If only TCP is open, players reach the server list but the handshake (UDP) never completes — a classic "stuck on connecting":
30120/tcp + 30120/udp game (default)
# both protocols must be openBecause the server list uses TCP but the handshake uses UDP, a firewall that allows TCP-only lets players SEE the server and then hang forever on "connecting". If everyone is stuck at the same point, check the UDP side of 30120 first.
Server side: a resource hanging the join
A heavy or broken resource can stall the connection deferral so players never finish loading. Watch the server console as a player joins — the last resource printed before the hang is your suspect. See fixing "couldn't load resource".
Client side: clear the cache
A corrupted client cache causes handshake and "o:err" failures. Have the player delete the FiveM cache:
%localappdata%\FiveM\FiveM.app\data\cache
# delete the cache folder contents, then relaunchOther quick checks
- Player should verify GTA V files in Steam/Rockstar/Epic.
- Disable mods/trainers in singleplayer — they break the handshake.
- Check the server's sv_maxclients isn't full and the server is updated to a current artifact.
- Make sure the server's connection deferral logic (loading screens/queue) isn't erroring.
Open 30120 on BOTH tcp and udp, watch the console for the resource that hangs the join, and clear the client cache for "o:err".
Other server-side causes worth checking
- Outdated FiveM server artifact — an old artifact build can be incompatible with the current client, producing handshake failures for everyone at once.
- txAdmin misconfiguration — a broken txAdmin recipe or a stuck restart can leave the resource loader half-initialised, which looks like a hang to joining players.
- Whitelist silently rejecting — a whitelist resource that errors instead of denying cleanly can present as a stuck connection rather than a clear "not whitelisted" message.
- ISP or routing issues between the player and the server — ask if the problem is universal (everyone) or local to one player before chasing server config.
How to prevent this
- Keep the FiveM server artifact updated on a regular schedule, not just when something breaks.
- Test resource load order after adding anything new, watching console timing for a resource that's visibly slow.
- Give players a clear, documented cache-clear + verify-files step to try before opening a ticket.
Related errors
If the client crashes rather than hangs, see fixing FiveM CitizenFX crashes. If the server isn't appearing in the list at all, see fixing FiveM server not showing in the list.
FiveM is a Cfx.re / Rockstar Games project. Grand Theft Auto V is a trademark of Rockstar Games / Take-Two Interactive. ESAGAMES is an independent hosting provider, not affiliated with or endorsed by Rockstar Games, Take-Two or Cfx.re. You must own a legitimate copy of the game.