Unable to ssh / An error occurred. Please contact administrator /

Unable to ssh / Unable to log in to backend ezsh shell / backend shell exits with 'An error occurred. Please contact the administrator.'

1. Check the user log file /home/{username}/ezsh.log for more details. 
2. Check the log file /var/log/secure for more error details
3. Ensure selinux is disabled. The command sestatus should return the value 'disabled'. Make sure to reboot the system after disabling selinux
4. Ensure that firewall is not blocking your ssh ports if you are ssh sessions are timing out.
5. ssh -v  user@_gatewayip would show more debug messages.
6. In /etc/ssh/sshd_config, make sure to comment the line AllowGroups in /etc/ssh/sshd_config and restart sshd, and try again.