AUTH/HANDSHAKE_MISSING_FIELDS
The server cannot verify the connection because the client did not provide the minimum required handshake auth information.
Classification
Application code. The wire value and spelling remain the same in every language. A registered code does not establish that its feature is active in every deployment.
Handling
Separate player reauthentication from server configuration or storage failures. Start a new provider flow when the login attempt is invalid; investigate signing configuration and storage on the server when appropriate. Never request a private key, mnemonic or callback token in a report.