Email Verification Process:
•Check email syntax is correct.
• Check if a domain name has MX records that exist.
•MX records reading (To get the MX records for a domain name or an email address).
• SMTP Server Checking (To verify SMTP server is working well and accept incoming connections).
•Checking your mailbox is valid. A service of this nature can't be 100% accurate thanks to factors outside our control, such as:
• Email server not contactable or down
• No mail servers defined for a website
• Busy email server • mailbox is full
• Some Internet Service Providers and email servers take strong anti-spam measures and we get the wrong results.
Specifically, Mail servers that are configured to always respond that an email address exists, but we get a BAD result on whether the result should be OK.