Пожалуйста, проверьте ниже пунктов
1) USER exist on jenkins server as same on linux machine.
2) SSH Public key shared on Jenkins server is correct.(manage jenkins --> manage user --> click on ${USER} --> click on configure --> then check ssh public key is correct).
3) CMD i used(working) --> java -jar jenkins-cli.jar -ssh -user ${USER} -i ~/.ssh/id_rsa -s http://localhost:8080/jenkins/ build ${JOB_NAME}
пожалуйста, проверьте, выполняете ли выcmd от того же пользователя.
4) SSH port should be enable on Jenkins (go to manage Jenkins--> configure Global security --> SSH Server... set SSHD Port Fixed eg 38844)