How to reproduce:
1. Create a new Unity project and install the Friends package
2. Link the project to a Unity Cloud project ID in Project Settings -> Services
3. Import the attached "Repro" script and attach it to any GameObject
4. Enter Play Mode
5. Observe the Console
Expected results: A client error such as HTTP 404 is returned with a "player not found" style message the game can show to the user
Actual results: The backend returns HTTP 500 Internal Server Error and the SDK throws "FriendsServiceException: Something went wrong." with Reason=Unknown and ErrorCode=Unknown
Reproducible with: 1.2.0 (6000.5.9f1)
Reproducible on: Ubuntu 24.04.4 LTS, macOS Tahoe 26 (M1)
Not reproducible on: No other environment tested
Note: Reproduced 3/3 with the names "NoSuchPlayer#0000", "Qwertyuiop#1234" and "Zxcvbnmasd#9876", spaced 12 seconds apart so the rate limiter is not involved. "Player#notanumber" returns the same 500. Any game with an "add friend by name" field will show a generic "Something went wrong" whenever a player mistypes a name.
The SDK also maps HTTP 429 Too Many Requests to Reason=Unknown / ErrorCode=Unknown, so a game cannot tell rate limiting apart from a genuine failure. Other codes are mapped correctly (InvalidCreateTarget 24033, FriendshipDoesNotExist 24013, SwaggerValidation, RelationshipNotFoundException).
First lines of error:
Unity.Services.Friends.Exceptions.FriendsServiceException: Something went wrong.
---> Unity.Services.Friends.Http.HttpException`1: (500) HTTP/1.1 500 Internal Server Error