I'm totally lost by the mail function in WordPress (WP 4.6 multisites).
I tested locally (on my localhost) WordPress send mail. This works fine at first sight (I don't really know why because I've never configured any SMTP server address in WordPress). When a user is created, a notification mail is correctly sent to the right address.
BUT, if I try to use the wp_mail() function in one of my theme pages, it just doesn't work! If I use instead the mail() php function, it works perfectly. (php mail() is set on my smtp server 'smtp' which is set on my provider's SMTP server, with a valid 'sender address')
There is about the same question here (Dead link, question was removed). The difference is that in my case, wp_mail() does work in the dashboard part but not in my theme... MANY thanks to you for a track, Pierre. (hope this post will be posted ! :)