Can MainWP send a new post notification with SMTP plugin such as Subscribe2?

Hi,
I’m using wordpress version 5.2.
My question is MainWP plugin is to post on multisites with a new post notification e-mail by using Subscribe2 plugin.
Now I’m testing to post on multisite(subdirectories) with MainWP plugin.
What I would like to do is to post on 2 subdirectory sites and to send a notification mail to 2 users (User A and User B
I succeeded on a post on subdirectory sites with MainWP plugin, but couldn’t send the notification mail to them.

Any advise will be appreciated.

If this is not appropirate forum I should ask, please advise me where to ask my question.

Best Regards,