@Hamilton Castro The error message indicates that you are running ambari agent on the same ambari server host? Or is it by mistake? We see "localhost" there Error:Request to https://localhost:8441/agent/v1/register/localhost . So please check few things: 1. The hostname is correct? Ambari relies on FQDN. Run on ambari server host to findout it's FQDN # hostname -f Also verify is ambari has opened port 8440 and 8441 on all available interface address: # netstat -tnlpa | grep `cat /var/run/ambari-server/ambari-server.pid` tcp6 0 0 :::8080 :::* LISTEN 13126/java tcp6 0 0 :::8440 :::* LISTEN 13126/java tcp6 0 0 :::8441 :::* LISTEN 13126/java 2. Also please check the ambari-agent.ini file to findout if it is pointing to the correct ambari server FQDN? # grep -A5 '\[server\]' /etc/ambari-agent/conf/ambari-agent.ini [server] hostname = ambariserver.example.com url_port = 8440 secured_url_port = 8441 connect_retry_delay = 10 max_reconnect_retry_delay = 30 . Also please verify if the "/etc/hosts" file is correct and it has the first two lines present as the note mentioned in https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.2.0/bk_ambari-installation-ppc/content/edit_the_host_file.html Do not remove the following two lines from your hosts file. Removing or editing the following lines may cause various programs that require network functionality to fail. . ... View more