Admin Portal validation for Backend's System Names field is case sensitive. However, the database is not.
This configuration allows Admin Portal to send Create Backends requests with System Names that already exists (from database perspective), distinguished only by their case structure.
When doing so, the Database generates a RecordNotUnique error, which leads to a 500 response (Internal Server Error).
When the same request for creating a Backend is made through the Account Management API, the error returned is a 409 (Conflict), which is actually a clearer response than a
generic error as 500 (Internal Server).
Bugsnag issue is THREESCALE-5046.