If your email recently delivered to Junk or Spam folder of Google Email, therefore you need to ask recipient to do some things. Basically if you already ask technical support for help but the issue keep arise, a workaround from recipient end is needed.
For your information, Google has developed their own filtering email system. Sometime, emails might went to Inbox or to Spam folder.
In this case, Google has advised to create own filtering system under recipient end.