Sol. mail

You're referring to a solution mail!

A solution mail, also known as a solution email or sol. mail, is a type of email that is used to provide a solution or answer to a problem or question that was previously raised in an email or discussion.

In other words, a solution mail is a follow-up email that provides a resolution or a solution to a specific issue or problem that was previously discussed or reported.

For example, if someone sends an email asking for help with a technical issue, and you send a follow-up email with a solution or a fix, that would be considered a solution mail.

Solution mails are often used in customer support, technical support, or help desk environments to provide timely and effective solutions to customers or users who are experiencing issues or problems.