Summary of 3-Day Debugging Session
We have been testing this issue extensively over the past three full days, documenting every single test run and behavior observed. The bug we’re encountering is extremely inconsistent and difficult to isolate.
We began by removing two major custom devices containing extensive Verse logic. After doing so, the issue appeared to be resolved — the map ran for 1.5 hours without any joining problems.
Encouraged by that result, we began reintroducing one of the main devices and started removing logic step by step inside the OnBegin function to pinpoint the problem.
It looked promising at first — previously, the issue would occur after 30–40 minutes if we are in the map with 4 players, but with some code disabled, it seemed delayed. However, after we thought it was finally resolved (and that we found which lines could potentially delay it), the bug returned again — this time after 1 hour and 30 minutes.
This delay-based failure is incredibly confusing. Disabling certain code doesn’t remove the bug, it just seems to delay it. We also noticed that the bug appears noticably faster with more players (e.g., 8) than with fewer.
At this point, we’re not even confident anymore that deleting our custom devices guarantees long-term stability. We can not rule out the possibility that the bug still exists and possibly would appear even after 4+ hours, this is something we might also test.
Normally, I’m all for debugging and testing on my own — that’s what we’ve been doing, 12 hours a day for the last few days — but I’m honestly starting to lose hope that this can be solved without direct support from the UEFN team.
We’ll keep testing more scenario’s and keep you up to date.
Update:
I changed two small things before I went to sleep:
- I removed some PlayerJoin / PlayerSpawn / PlayerLeave handlers, which had minimum code
- I removed my 8 old spawn pads and placed 1 fresh one back
This was active with 2 players for minimum of 10 hours.
In the morning, I tried to rejoin with Player A, which was in this lobby for 10 hours. I received the following NEW error, Matchmaking error #2. I have attached the log.
A fresh account was able to join this lobby without any issues.
What completely confuses me is that the test I did without these 2 minor changes, resulted into the bug appearing after 1h30m. When I really look at the code I disabled after, it should not have had any impact at all..
FortniteGameMatchmakingError2.log (2.7 MB)