"Could not instantiate mail function" is not a helpful error message

[ghost]

Problem description

"Could not instantiate mail function" is not a helpful error message. It seems to be a catch all for many different conditions (invalid parameters like not a valid mail address, problems locating sendmail, no permission to run sendmail, ...). sendmail is installed, so this error message tells me absolutely nothing except that some random thing is wrong. This is extremely frustrating. Therefore, please find a way to provide a better error message.

Code to reproduce

use php mailer example on a system e.g. without sendmail

Debug output

[Synchro]

I can't tell. The only thing I have to go on is the boolean returned by the mail() function. PHPMailer isn't (and shouldn't be) responsible for your entire PHP and OS configuration; it's just a small component. That said, you might like to put some effort into the diagnostic utility idea in #612; PRs welcome.

I strongly recommend (as do the docs) not using mail() anyway since it's impossible to use securely, and it's also slower and provides less feedback (as you're finding) than SMTP to localhost.