PHP mails not working with Wordpress multisite
I'm currently setting up a staging environment for my Wordpress websites and need some help regarding emails not being sent.
I've started by using the Wordpress one-click installation provided by DigitalOcean. Then I went ahead and created a Wordpress network to allow the installation of multiple sites. This is probably where it went wrong: now I'm not receiving any mails when I try to register users or fill in the "Forgot my password" form.
Guessing this has something to do with the PHP mail settings, I went ahead and opened the PHP.ini, but I couldn't figure out what was wrong. Then I tried to send an email using:
mail ('firstname.lastname@example.org', "Testmail", "Test mail from my staging environment");
And noticed this also wouldn't work.
Does anybody know what's wrong here and how I can debug this?
Thanks in advance!