While logging to user with shell access the following error was getting generated.

-jailshell: fork: retry: No child processes
-jailshell: fork: retry: No child processes
-jailshell: fork: retry: No child processes
-jailshell: fork: retry: No child processes
-jailshell: fork: Resource temporarily unavailable

Simply killed the resource intensive process of the user to fix the issue.

for i in `ps aux | grep username | awk '{print $2}'`; do kill -9 $i; done

for i in `cat /proc/mounts | grep username | awk '{print $2}'`; do umount $i; done

• CentOS
• cPanel
• Linux