The requested networking protocol has not been configured into the system, or no implementation for it exists. (A protocol is a formal description of the messages to be exchanged and the rules to be followed when systems exchange information.)
Verify that the protocol is in the /etc/inet/protocols file and in the NIS protocols map, if applicable. If the protocol is not listed, and you want to permit its use, configure the protocol as documented or as required.
The symbolic name for this error is EPROTONOSUPPORT, errno=120.