You may face the below error while switching the accounts using the su command.
# su accutest
su: cannot create child process: Resource temporarily unavailable
If you are facing this issue, it means CageFS (virtual file system per user) is not enabled for the same user because shell access is unavailable to the user's environment.
Please refer to the following commands to enable CageFS –
# /usr/sbin/cagefsctl --enable accutest
Run the su command again, and you shouldn't face the same issue again.
Want to know the difference between su and sudo user?
Please refer to Linux > Sudo v/s Su User for more details.