Unknown messages come to your e-mail from different e-mail boxes. Now there are many scammers who are trying to use all sorts of tricks to hack users' emails and "cheat" them for money. Before opening the letter, you need to very carefully study the data about the person from whom the message came. How can you find out the owner of the box?
If you need to find out the owner of a particular email address, then look for information about him in search engines such as Yandex or Google. Just enter the desired email address in the search box. And you will be surprised when the system shows you a lot of data. If such a postal address has ever been registered on the Internet, at least once, then the system, of course, will give you these requests. There are other possibilities for finding the information you are looking for.
Ask users on the forums about the mailing address of interest. Perhaps there are people who have come across a similar box. Maybe this is some kind of mailing list, so you are not the only one who received the corresponding letters. If you find at least some information related to the desired address, then you can make a request to the official service, which will provide a domain name for mail.
Try to write a message to your mailbox so that you will be answered. As soon as a letter comes from the desired user, you can see his IP address from which the message was sent, and then find the location where the desired owner of the box lives. And in this regard, the list of users with the address of interest should be reduced.
Find the owner of the email address using social media, as there is a huge number of users there. So, if the mailbox is registered on the mail.ru server, then you can search for the owner of the email address using the "My World" project. And if you are registered on Yandex, then search by mail for the right person on the Ya.ru network. You can go to such social networks as "Vkontakte", "Odnoklassniki.ru", Facebook. To do this, you need to use the built-in search.