bench new-site erp.example.com failed

Install / Update Setup
4

I have Tried following links in all to install ERPNext
https://www.vultr.com/docs/how-to-install-erpnext-open-source-erp-on-centos-7
https://www.vultr.com/docs/how-to-install-erpnext-open-source-erp-on-ubuntu-17-04-22771