Code,Description,Reference
300,"Incompatible network protocol: One or more network   
protocols contained in the session description are
not available.",[RFC3261]
301,"Incompatible network address formats: One or more    
network address formats contained in the session
description are not available.",[RFC3261]
302,"Incompatible transport protocol: One or more         
transport protocols described in the session
description are not available.",[RFC3261]
303,"Incompatible bandwidth units: One or more bandwidth  
measurement units contained in the session
description were not understood.",[RFC3261]
304,"Media type not available: One or more media types    
contained in the session description are not
available.",[RFC3261]
305,"Incompatible media format: One or more media formats 
contained in the session description are not
available.",[RFC3261]
306,"Attribute not understood: One or more of the media   
attributes in the session description are not
supported.",[RFC3261]
307,"Session description parameter not understood: A      
parameter other than those listed above was not
understood.",[RFC3261]
308,Incompatible language specification: Requested languages not supported.  Supported languages and media are: [list of supported languages and media].,[RFC8373]
330,"Multicast not available: The site where the user is  
located does not support multicast.",[RFC3261]
331,"Unicast not available: The site where the user is    
located does not support unicast communication
(usually due to the presence of a firewall).",[RFC3261]
370,"Insufficient bandwidth: The bandwidth specified in   
the session description or defined by the media
exceeds that known to be available.",[RFC3261]
380,"SIPS Not Allowed: The UAS or proxy cannot process    
the request because the SIPS scheme is not allowed
(e.g., because there are currently no registered
SIPS Contacts).",[RFC5630]
381,"SIPS Required: The UAS or proxy cannot process the   
request because the SIPS scheme is required.",[RFC5630]
399,"Miscellaneous warning: The warning text can include  
arbitrary information to be presented to a human user
or logged. A system receiving this warning MUST NOT
take any automated action.",[RFC3261]