Have you sent an email, but have not received a response? Check if such an address and mailbox exist. Check the validity of contact information.
The measurement accuracy depends on the settings of the email server. The most correct results are obtained when checking the emails of the most popular email services: Google, Yahoo, Yandex, Mail.ru and others.
In short, we send a greeting to the mail server of the entered email address and receive a response. If we don't get a response, then the email address is marked as not existing.
However, this does not mean that it actually does not exist. It is possible that the email server is specifically configured not to send replies to such greetings.
You can also try to send email to this address. If you do not receive a message with an error within 24 hours, then most likely the address exists. Information about the error can also be in the logs of your email server if you have a private server for sending emails.
Please note that the service is not suitable for checking a large number of email addresses. Use specialized programs for this. In case of exceeding an adequate number of requests, a CAPTCHA will be displayed or your IP address will be blocked by a firewall.