Hi dear site owner, 
 
If you received this letter, it means that your site has a vulnerability and is potentially susceptible to various types of automatic attacks. 
 
Write "I want a report" to this email address - pentesting4u@yandex.com and specify your site. Within a few days we will send information about vulnerabilities that hackers can use to harm your site or server. 
 
Sincerelly, 
Your pentest team