How to make a request to send a message?

Question

Automation

Good day, the task is what, you need to automate the sending of letters to mail.ru. What is the problem, but in what, in order to send a message, you need cookies (which already exist) and a token that comes from nowhere. We need to find out where it comes from. I work in soapui, I do it for myself. This token is contained in the body of the V1 request, which is received when the email is sent.