I’ve forgot that my server does not have that email function.
Had to install SMTP mail plugin. I’ve set the google OAuth 2.0, tested out by “test email function” and recieved test email.
After the changes I’m getting error “Cannot send email – problem with send server”
this case I think, you should contact us through the internal support for our developers department checking. Please, provide us there all the credentials to your site and FTP. they will fix it as soon as possible