Linux & UE 5.6 - Unable to open fab from within engine

TheDarkTrav3l3r · June 11, 2025, 4:12pm

Summary

Unable to use Fab from within UE 5.6

What type of bug are you experiencing?

Plugins

URL where the bug was encountered

Steps to Reproduce

Open Unreal Engine
Click Fab

(also seems to apply to MH Creator)

Expected Result

I would see Fab within UE

Observed Result

Error in screen shot and below

From command line output:

[2025.06.11-16.00.22:098][820]LogFab: Display: Logging in using persist
[2025.06.11-16.00.22:098][820]LogEOSSDK: Warning: LogEOSAuth: No existing persistent auth credentials were found for automatic login.
[2025.06.11-16.00.22:114][820]LogFab: Error: Login failed - error code: EOS_InvalidAuth
[2025.06.11-16.00.22:114][820]LogFab: Display: Logging in using exchange code
[2025.06.11-16.00.22:114][820]LogFab: Display: Reading exchange code from commandline
[2025.06.11-16.00.22:114][820]LogEOSSDK: Error: LogEOSAuth: Invalid parameter EOS_Auth_Credentials.Token reason: must not be null or empty
[2025.06.11-16.00.22:136][821]LogFab: Error: Login failed - error code: EOS_InvalidParameters

Platform

UE 5.6

Operating System

Linux, Arch, Brave

Upload an image

True_poser · June 14, 2025, 9:10pm

I have the same outcome (ERR_NAME_NOT_RESOLVED when trying to open Fab window in-editor) with slightly different log entries.

LogFab: Display: Logging in using persist
LogWebBrowser: Loaded CEF3 version 128.4.13.3057 from
LogCEFBrowser: CEF GPU acceleration enabled
LogEOSSDK: LogEOSAuth: UpdateUserAuthToken: User ClientId: <deleted_by_me> AccountId: <deleted_by_me> Access[Expires: 2025.06.14-20.47.04 Remaining: 7200.36] Refresh[Expires: 2025-12-11T18:30:35.037Z Remaining: 15551011.04] State: Valid
LogEOSSDK: LogEOSAuth: UserAuthGenerated: Received FUserAuthToken
LogEOSSDK: LogEOSAuth: UserAuthGenerated: Login complete: EOS_Success
LogFab: Display: User logged in
LogFab: Display: User client id: [deleted_by_me]
LogEOSSDK: Warning: LogEOS: Error response received from backend. ServiceName=[Friend], OperationName=[GetBlockList], Url=[], HttpStatus=[403], ErrorCode=[errors.com.epicgames.common.insufficient_scopes], NumericErrorCode=[1056], ErrorMessage=[Insufficient access scopes. Expected: [friends_list]], CorrId=<deleted_by_me>

UE version: 5.6, downloaded from https://www.unrealengine.com/en-US/linux
Fab plugin was downloaded from the same location.
Linux: CachyOS current.

Thank you.

TheDarkTrav3l3r · June 15, 2025, 4:41pm

I compiled from GH so it is universal

TheDarkTrav3l3r · June 16, 2025, 5:19pm

I’ve delved a little deeper. It doesn’t appear to be a permissions issue or at least nothing from Engine/Binaries/Linux/EpicWebHelper

Running a packet capture just says the connection is happening. Still the same result.

I have confirmed it is the same thing when you go into Quixel and try to login.

Really wish I could use UE.