Cannot create an x.509 user with a subjectname that would be recognized as an internal cluster member

[join_mic]

when I send
db.getSiblingDB("$external").runCommand({createUser:"CN=192.168.31.100,OU=KernelUser,O=MongoDB,ST=New York,C=US",roles:[{role:'root',db:'admin'}]})

,return the error:

Cannot create an x.509 user with a subjectname that would be recognized as an internal cluster member.

why?
I do all follow “Cloud: MongoDB Cloud”

[Ramachandra_Tummala]

May be the server and client certificates are using same values for O,OU fields
DN(distinguished name) from client certificate subject should differ from that of server

[join_mic]

Yeah! Is solved! I change the ‘CN=127.0.0.1’ to ‘CN=192.168.31.100’,
and ready another visualserver for client ,

Server.pem(192.168.31.100):
subject= CN=192.168.31.100,OU=KernelUser,O=MongoDB,ST=New York,C=US

Client.pem(192.168.31.110):
subject= CN=customer,OU=customer,O=MongoDB,ST=New York,C=US

thank you very much!