The error code 4975 occurs when attempting to link a Steam account with an EA account while launching an EA game through Steam.
This error indicates that EA's authentication servers have rejected the linking request due to the account not meeting certain security or eligibility requirements.
EA's authentication tokens can expire or become mismatched with the current Steam session if they haven't been refreshed recently, resulting in an invalid token and a rejected linking request.
Author's summary: Fixing EA error 4975 requires resolving authentication issues.