Hello,
I’m having same problem but neither option (php mail or wp-mail works). The only time it works is if it’s sent to an email address that was originally registered when I setup wordpress. If I change the email address for Admin to new one, it doesn’t send the email and comes up with same error message, “Sorry, email message could not be delivered.” :/ I tried to send it to a different users as well but no luck. The only email that works is the original one. :/ Any ideas please?