Error: unauthorized :: The client lacks sufficient authorization :: Error creating new authz :: Name is not whitelisted

webroot doesn't require to stop the existing web server for domain validation itself.. but once you get the LE ssl certificate you will then need to configure it manually or automate it with your web server and part of that process is restarting the web server for the new LE SSL certificate to take effect

Examples of Letsencrypt client's webroot authentication plugin in it's various evolving forms can be found in the following links

My specific examples for LE webroot integration into my Nginx stack installer + auto renewal support every 60 days at

[quote="svddevelop, post:7, topic:2193"]
what need to do and how can to append "Name to whitelist" ?
[/quote] did you apply to be in beta invite and submit domains for whitelisting ?