Today one of the cPanel user shell access gives error as follows:
su - user -bash: fork: Resource temporarily unavailable
The error occurs due to cPanel and its “Shell Fork Bomb Protection”.
To fix this issue,
Go to Security >> Security Center
Shell Fork Bomb Protection and click on “Disable Protection”
It will resolve the issue.
Shell Fork bomb Protection will prevent users with terminal access (ssh/telnet) from using up the server’s resources and possibly crashing the server.