You may see error “Fatal! Write failure” error message while adding email forwarders OR setting a catchall email address from cPanel >> “Email Accounts” section. The error is:
Fatal! Write Failure: /etc/valiases/domainname.tld. Ignore any messages of success this can only result in failure!
The reason is the /etc/valiases/domainname.tld file is missing OR having incorrect permissions. In order to correct the valiases file, ssh to your server as root and create the file with the appropriate permissions:
chown user.mail domainname.tld
chmod 644 domainname.tld
Once the valiases file is created for the user with appropriate permissions, you will be able to add email forwarders and catchall email address from cPanel again.