it looks you are running in centos VPS.
1. You have to check your SELINUX first using command getenforce and the results should be Disabled
To disable SELINUX, login on your VPS using root user and you can type command getenforce 0 to set disable.
2. Second please try to disable your firewall
To check if you have running firewall you can type command on your root login using command
iptables -nL OR systemctl status firewalld
you can temporary disable your firewall using command
systemctl stop firewalld then try to connect again on your RO client.
if the issues is firewall, you have to configure your firewall properly and open specific port only.
NOTE: DISABLE FIREWALL IS NOT SAFE, IT MAY CAUSE YOUR SERVER OPEN TO PUBLIC.