I’m also seeing this on Java 26.3 when uploading an existing Realm world.
The upload reaches 100% and then reports:
Upload failed! (504)
However, the world itself is actually applied to the Realm correctly — all terrain and builds are present.
The problem is that the existing player data is not preserved. Players join with reset/missing inventory, XP and position.
I have confirmed that the source world contains valid player data before upload under:
players/data/<UUID>.dat
and the inventories/XP/positions are correct when the world is opened locally.
I have reproduced this after downloading the Realm, reducing the world size by removing unused chunks, and uploading it again. The result is still:
100% upload → 504 error → correct world uploaded → player data missing/reset.
This suggests the 504 may be happening during the Realms import/processing stage after the world data has already been transferred, and that the player data is being lost or ignored during that process.
I can provide the source save and screenshots if useful.
Smartie
I’m also seeing this on Java 26.3 when uploading an existing Realm world.
The upload reaches 100% and then reports:
Upload failed! (504)However, the world itself is actually applied to the Realm correctly — all terrain and builds are present.
The problem is that the existing player data is not preserved. Players join with reset/missing inventory, XP and position.
I have confirmed that the source world contains valid player data before upload under:
players/data/<UUID>.datand the inventories/XP/positions are correct when the world is opened locally.
I have reproduced this after downloading the Realm, reducing the world size by removing unused chunks, and uploading it again. The result is still:
100% upload → 504 error → correct world uploaded → player data missing/reset.
This suggests the 504 may be happening during the Realms import/processing stage after the world data has already been transferred, and that the player data is being lost or ignored during that process.
I can provide the source save and screenshots if useful.