What basic knowledge should one have before buying Unlimited SMTP, Webmail, Mailer, RDP ?

IP Server blacklist check:

BUT Spamhaus: Clear

AND DKIM WHAT 'S DKIMRead More

If you use SMTP to spam domain mail, 126.com, yahoo, Yandex & aol. You should use it.

Standard of SMTP.

Because of private server was not registered with major anti-spam organizations. Unlimited SMTP cannot send inbox to popular email providers like: Gmail, AOL, Outlook, Yahoo...etc

Test Deliver:

Title & Messenger: Best Good For You.

+ Yahoo, Aol ( Spam )
+ Yandex ( Inbox or Spam )
+ 126.com ( Inbox or Spam )

+ Domain mail don't have a system to filter mail, fight spam, Block ads, Block phishing mails: Inbox

    Company Emails ( Domain mail ) created from the company server. They don't have a system to filter mail >> Deliver Inbox.

+ Domain mail have a system to filter mail, fight spam, Block ads, Block phishing mails: Inbox or Spam or Not Deliver ( ex:
   hosting provider: GoDaddy,Hostgator ... etc)

   There are many companies buying server or hosting from providers. They also have a system to filter mail. Their email filtering
   system is weak or strong. DKIM, SPF Unlimited SMTP easy to pass. if SMTP don't pass. It's mean their email filtering system is
   strong. >> Not Deliver

This 's video & demo:

Unlimited SMTP - Full DKIM, SPF, Private Domain, Private IP

What basic knowledge should one have before buying Unlimited SMTP, Webmail, Mailer, RDP ?