Code,Reason,Description,Reference
100,<reason> (see Description),Generic informational error-code meant for carrying a human-readable string,[RFC7975]
400,<reason> (see Description),Generic error-code for uCDN errors where the dCDN cannot or will not process the request due to something that is perceived to be a uCDN error. The reason field may be used to provide more details about the source of the error.,[RFC7975]
500,<reason> (see Description),Generic error-code for dCDN errors where the dCDN is aware that it has erred or is incapable of satisfying the RI request for some reason. The reason field may be used to provide more details about the source of the error.,[RFC7975]
501,Unable to retrieve metadata,The dCDN is unable to retrieve the metadata associated with the content requested by the UA. This may indicate a configuration error or that the content requested by the UA does not exist.,[RFC7975]
502,Loop detected,The dCDN detected a redirection loop (see Section 4.8 of [RFC7975]).,[RFC7975]
503,Maximum hops exceeded,The dCDN detected the maximum number of redirection hops exceeding max-hops (see Section 4.8 of [RFC7975]).,[RFC7975]
504,Out of capacity,The dCDN does not currently have sufficient capacity to handle the UA request.,[RFC7975]
505,Delivery protocol not supported,The dCDN does not support the (set of) delivery protocols indicated in the CDNI Metadata of the content requested by the UA.,[RFC7975]
506,Redirection protocol not supported,The dCDN does not support the requested redirection protocol.  This error-code is also used when the RI request has the dns-only flag set to True and the dCDN is not supported or is not prepared to return an RT of a surrogate directly.,[RFC7975]