Code,Meaning,Reference
200,Success,[RFC6787]
201,Success with some optional header fields ignored,[RFC6787]
401,Method not allowed,[RFC6787]
402,Method not valid in this state,[RFC6787]
403,Unsupported header field,[RFC6787]
404,Illegal value for header field.  This is the error for a syntax violation.,[RFC6787]
405,Resource not allocated for this session or does not exist,[RFC6787]
406,Mandatory Header Field Missing,[RFC6787]
407,"Method or Operation Failed (e.g., Grammar compilation failed in the recognizer.  Detailed cause codes might be available through a resource specific header.)",[RFC6787]
408,Unrecognized or unsupported message entity,[RFC6787]
409,Unsupported Header Field Value.  This is a value that is syntactically legal but exceeds the implementation's capabilities or expectations.,[RFC6787]
410,Non-Monotonic or Out-of-order sequence number in request.,[RFC6787]
411-420,Unassigned,
501,Server Internal Error,[RFC6787]
502,Protocol Version not supported,[RFC6787]
503,Unassigned,
504,Message too large,[RFC6787]