[SOLVED]! UEFN Validation Error: Fab Referenced Content (CGMA Studio Offices) Fails Module Validation Despite Being Purchased and UEFN-Compatible

General Issues and Bug Reporting
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1

SOLVED

My mistake! In addition to the Referenced Content Asset, I had a migrated version of the asset that wasn’t showing up in UEFN! I was able to delete it using the file manager, and since then the Referenced Content Asset “CGMA Studio Offices” has been working again! By the way, it’s a really beautiful asset, like so many from Dekogon!

Thanks for your help!

Old problem:

Summary

Purchased and legally obtained Fab asset “CGMA Studio Offices” that is marked as UEFN-compatible fails module validation when attempting to launch/test the island, preventing project publication despite being properly installed as Referenced Content.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Assets

Steps to Reproduce

  1. Purchase “CGMA Studio Offices” from Fab.com (marked as UEFN-compatible)
  2. Install as Referenced Content in UEFN 36.20 via Fab integration
  3. Use assets in level design
  4. Attempt to launch/test the island
  5. Validation fails with “CandidateApiJsonInvalid” error

Expected Result

Legally purchased Fab assets marked as “UEFN-compatible” should pass validation successfully and allow the island to launch for testing and publication without any validation errors.

The Referenced Content should be recognized as authorized content and not flagged as disallowed during the module validation process.

Observed Result

Module validation fails during launch with the following error:

“[CandidateApiJsonInvalid] Supplied candidate api does not match expected public api”

The system rejects hundreds of CGMA Studio Offices assets as “Extra” content that is not allowed, including:

  • CGMA Studio Offices/Blueprints/BP_Glass_Door_01a
  • CGMA Studio Offices/Materials/Instances/MI_Artwork_01a
  • CGMA Studio Offices/Meshes/Buildings/SM_BalconyRailing_Bend_1M_01a
  • [and many more assets from the pack]

Error occurs specifically during “FlowStep_ResolveSessionCandidates()” step.

Launch process completely fails with message:
“Failed to validate candidate module versions”

Dialog appears: “Unable to Play: Failed to validate candidate module versions”

The island cannot be tested or published despite using legally purchased, UEFN-compatible Fab content that was properly installed as Referenced Content through the official Fab integration.

Platform(s)

windows

Additional Notes

  • UEFN Version: 36.20
  • Asset: CGMA Studio Offices from Fab.com
  • Installation Method: Referenced Content via Fab integration
  • Error occurs during “FlowStep_ResolveSessionCandidates()”
  • Asset is legally purchased and marked as UEFN-compatible on Fab
  • No conversion options available (no “Make Writable” or similar)

Impact:
This prevents creators from using legally purchased, UEFN-marked Fab content in published islands, creating confusion about Fab/UEFN compatibility.

2

Hi @MagicThor,
You need to vote this up along with few others people
Taking a look at this IMHO its the “Cannot be used with Scene Graph Beta” that is the problem.
There is a lots of publishing error messages because “Scene Graph Beta” is experimentatal and you nned to check this.
There is a problem with 36.20 switching on “Scene Graph Beta” by default therefore Publishing validation will stop anything referencing “Experimental/Beta”. The “Extra” content is probably seen as Experimental. Could you try breaking/deleting the reference in content browser, which have done before to allow validation.
All materials must be imported as props
Perhaps you cannot do this on refence content.
Here is documentation
Importing Assets in Unreal Editor for Fortnite | Fortnite Documentation | Epic Developer Community

Try turning off “Scene Graph Beta” in myproject.uefnproject

This could be just another bug inUEFN 36.20

2 Likes
3

Thank you, again! :slight_smile: But I’m not using experimental / beta in my project… :slight_smile:

No_SceneGraph
No_SceneGraph1521×532 41 KB

4

Dear @Jimbohalo10 , thanks again for helping me! :slight_smile:

It’s now solved… It was realy my mistake! In addition to the Referenced Content Asset, I had a migrated version of the asset that wasn’t showing up in UEFN! I was able to delete it using the file manager, and since then the Referenced Content Asset “CGMA Studio Offices” has been working again! UEFN 36.10 had no problem with it…

1 Like