Why i cant launch my session please ?

Development Programming & Scripting
, ,
1

Hi everyone,

I’m having an issue when trying to launch a session in UEFN. My project was created directly in .

When I click on Launch Session, I get the following error in the output log:

LogValkyrieSyncProject: Error: Failed to Query project dependency API: Failure ErrorCode=errors.com.epicgames.content-service.MODULE_NOT_FOUND, Message=Une erreur est survenue lors de la communication avec les serveurs de jeu (Could not find the requested resource)., Raw={ “host”: “content-service.bfda.live.use1a.on.epicgames.com”, “method”: “GET”, “path”: “/api/content/v4/module/dff8b3b9-491a-074d-55a7-949d4e1c4700/version/2/staged-files/public/api.json”, “errorCode”: “errors.com.epicgames.content-service.MODULE_NOT_FOUND”, “errorMessage”: “Could not find the requested resource” }

What I’ve already tried:

  • The UUID (dff8b3b9-491a-074d-55a7-949d4e1c4700) does not appear anywhere in my .uefnproject file
  • I noticed this issue started after the UEFN 40.00 update

Any help would be appreciated, thanks!

2

Hi,

That error usually points to a missing or broken reference on Epic’s content service side rather than something directly in your project files. Since it started after the 40.00 update, there’s a good chance something didn’t migrate cleanly.

A few things you could try:

  • Clear local cache (UEFN/DerivedDataCache) and restart the editor

  • Re-sync the project from source control (if you’re using it) or re-download from Epic services

  • Try duplicating the project and launching the session from the copy

  • Check if all plugins/modules used by the project are still available and enabled after the update

  • Log out and back into Epic Games in UEFN (sometimes auth issues trigger weird API errors)

If the UUID isn’t in your .uefnproject, it might be referencing an old or deleted module on Epic’s backend. In that case, recreating the affected asset or re-linking dependencies might help.

We’ve run into similar post-update inconsistencies while working on projects at Playvera Labs — updates can sometimes leave behind broken remote references. If none of the above works, it might be worth reporting it to Epic with the full log, since it could be a backend issue on their side.