public bool isNetworkError { get; }

Examples of system errors include failure to resolve a DNS entry, a socket error or a redirect limit being exceeded. When this property returns , the UnityWebRequest.error property will contain a human-readable string describing the error.

Note: Error-type server return codes, such as 404/Not Found and 500/Internal Server Error, are reflected in the UnityWebRequest.isHttpError property, not the UnityWebRequest.isNetworkError property.

Additional Resources: UnityWebRequest.responseCode, UnityWebRequest.isHttpError.