Description of the bug
Jellyfin 10.12.0 (nightly/latest) appears to default EnableLegacyAuthorization in system.xml to false, which breaks authentication for Jellyseerr and likely other third-party applications. This will cause widespread breakage when 10.12 is released unless addressed.
Environment:
-
Jellyfin Version: 10.12.0 (build 2025122905) pulled from jellyfin/jellyfin:latest
-
Jellyseerr Version: 2.7.3 (fallenbagel/jellyseerr:latest)
-
Installation Method: Docker
-
OS: Ubuntu Server
Reproduction steps
- Install Jellyfin 10.12.0 (nightly Docker image)
- Install Jellyseerr 2.7.3 or older versions
- Attempt to authenticate with Jellyfin credentials through Jellyseerr
- Authentication fails with errors:
- Failed to authenticate with headers: error=Bad Request (400)
- Failed to authenticate with headers: error=Not Found (404)
What is the current bug behavior?
Authentication fails completely with generic "something went wrong" errors. No amount of URL format changes, API key regeneration, or fresh installations resolve the issue.
What is the expected correct behavior?
Jellyseerr should successfully authenticate with Jellyfin using username/password, as it does with Jellyfin 10.10.7 and 10.11.5.
Jellyfin Server version
Unstable
Specify commit id
No response
Specify unstable release number
2025122905
Specify version number
10.12.0
Specify the build version
2025122905
Environment
- OS:
- Linux Kernel:
- Virtualization:
- Clients:
- Browser:
- FFmpeg Version:
- Playback Method:
- Hardware Acceleration:
- CPU Model:
- GPU Model:
- Plugins:
- Reverse Proxy:
- Base URL:
- Networking:
- Jellyfin Data Storage & Filesystem:
- Media Storage & Filesystem:
- External Integrations:
Jellyfin logs
Jellyseerr logs:
2026-01-06T16:33:38.497Z [debug][Jellyfin API]: Failed to authenticate with headers {"error":"Not Found","ip":"172.20.0.20"}
2026-01-06T16:33:38.811Z [error][Jellyfin API]: Something went wrong while authenticating with the Jellyfin server: Request failed with status code 404 {"error":404,"ip":"172.20.0.20"}
2026-01-06T16:33:47.814Z [debug][Jellyfin API]: Failed to authenticate with headers {"error":"Bad Request","ip":"172.20.0.20"}
2026-01-06T16:33:48.582Z [error][Jellyfin API]: Something went wrong while authenticating with the Jellyfin server: Request failed with status code 400 {"error":400,"ip":"172.20.0.20"}FFmpeg logs
Client / Browser logs
No response
Relevant screenshots or videos
No response
Additional information
Impact:
Jellyseerr is widely used in the Jellyfin ecosystem as the primary request management system
Thousands of users will experience broken authentication when upgrading to 10.12
The error messages are cryptic and don't indicate the root cause
No coordination appears to have occurred with the Jellyseerr development team to update their authentication implementation before this change
Related Issues:
#15153 - Users reporting authentication issues with 10.11
seerr-team/seerr#1925 - Jellyseerr authentication failures
jellyfin/Swiftfin#1859 - Swiftfin reporting same issue with 10.12
Request:
Please either:
Keep EnableLegacyAuthorization=true as the default in 10.12.0 to give third-party apps time to migrate
Coordinate with major third-party app developers (Jellyseerr, Kodi, etc.) before deprecating legacy auth
Prominently document this breaking change in 10.12 release notes with clear migration instructions
Provide a migration timeline so third-party developers know when they must update
The Jellyfin 10.11.0 release notes mention "We're planning to remove old authorization methods in 10.12.0" but don't clarify whether EnableLegacyAuthorization will be disabled by default or removed entirely. This needs clear communication.
Additional Context:
I spent several hours troubleshooting this issue, rolling back versions, clearing caches, and testing different configurations before discovering the EnableLegacyAuthorization flag was the root cause. Most users won't figure this out and will simply report "Jellyseerr broken after updating Jellyfin."
Description of the bug
Jellyfin 10.12.0 (nightly/latest) appears to default EnableLegacyAuthorization in system.xml to false, which breaks authentication for Jellyseerr and likely other third-party applications. This will cause widespread breakage when 10.12 is released unless addressed.
Environment:
Jellyfin Version: 10.12.0 (build 2025122905) pulled from jellyfin/jellyfin:latest
Jellyseerr Version: 2.7.3 (fallenbagel/jellyseerr:latest)
Installation Method: Docker
OS: Ubuntu Server
Reproduction steps
What is the current bug behavior?
Authentication fails completely with generic "something went wrong" errors. No amount of URL format changes, API key regeneration, or fresh installations resolve the issue.
What is the expected correct behavior?
Jellyseerr should successfully authenticate with Jellyfin using username/password, as it does with Jellyfin 10.10.7 and 10.11.5.
Jellyfin Server version
Unstable
Specify commit id
No response
Specify unstable release number
2025122905
Specify version number
10.12.0
Specify the build version
2025122905
Environment
Jellyfin logs
Jellyseerr logs: 2026-01-06T16:33:38.497Z [debug][Jellyfin API]: Failed to authenticate with headers {"error":"Not Found","ip":"172.20.0.20"} 2026-01-06T16:33:38.811Z [error][Jellyfin API]: Something went wrong while authenticating with the Jellyfin server: Request failed with status code 404 {"error":404,"ip":"172.20.0.20"} 2026-01-06T16:33:47.814Z [debug][Jellyfin API]: Failed to authenticate with headers {"error":"Bad Request","ip":"172.20.0.20"} 2026-01-06T16:33:48.582Z [error][Jellyfin API]: Something went wrong while authenticating with the Jellyfin server: Request failed with status code 400 {"error":400,"ip":"172.20.0.20"}FFmpeg logs
Client / Browser logs
No response
Relevant screenshots or videos
No response
Additional information
Impact:
Jellyseerr is widely used in the Jellyfin ecosystem as the primary request management system
Thousands of users will experience broken authentication when upgrading to 10.12
The error messages are cryptic and don't indicate the root cause
No coordination appears to have occurred with the Jellyseerr development team to update their authentication implementation before this change
Related Issues:
#15153 - Users reporting authentication issues with 10.11
seerr-team/seerr#1925 - Jellyseerr authentication failures
jellyfin/Swiftfin#1859 - Swiftfin reporting same issue with 10.12
Request:
Please either:
Keep EnableLegacyAuthorization=true as the default in 10.12.0 to give third-party apps time to migrate
Coordinate with major third-party app developers (Jellyseerr, Kodi, etc.) before deprecating legacy auth
Prominently document this breaking change in 10.12 release notes with clear migration instructions
Provide a migration timeline so third-party developers know when they must update
The Jellyfin 10.11.0 release notes mention "We're planning to remove old authorization methods in 10.12.0" but don't clarify whether EnableLegacyAuthorization will be disabled by default or removed entirely. This needs clear communication.
Additional Context:
I spent several hours troubleshooting this issue, rolling back versions, clearing caches, and testing different configurations before discovering the EnableLegacyAuthorization flag was the root cause. Most users won't figure this out and will simply report "Jellyseerr broken after updating Jellyfin."