Problem sending emails


I have a Registration system and it requires for the user to confirm his email when he/she signup my problem is when the user uses Gmail account to register in my website the confirmation email didn’t send to his email and the odd thing is when another user with email lets say from register the message get send with no issue does that mean I can’t send emails to Gmail or what.
this is the code am using to send the messages

$mailHeader   = 'From:';
  $emailSubject = "Activate your Account. OvOnGames";
         $to           = $email;
         $body         = "
        Hello " . $username . " \n
        There's just one more step to go, and it's the easiest one yet.\n
        Click the link below to confirm your Account. \n
        " . BASE_URL . "/register/activiate.php?email=" . $email . "&code=" . $hashActiviateCode . " \n
        OvOnGames Best Free to play browser games";
          mail($to, $emailSubject, $body, $mailHeader);
        $success[] = "You Registered Successfully At OvOnGames Please check Your Email Inpox For Confirmation Code. ";


Good day!

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