Probably one of two things-
1) The email you have entered here-
https://vborg.vbsupport.ru/profile.php?do=editpassword - does not
exactly match what is in your priority forum support list in the Member's Area
or
2) You did not get/follow the activation instructions last time you changed your forum email address- you can request a new copy of the activation email here-
https://vborg.vbsupport.ru/register.php?do=requestemail
If neither help then open a support ticket in the Member's Area and include your vBulletin.org username and explain the situation.