Could not instantiate mail function error

If you're receiving a Could not instantiate mail function error, this can be generated by a bunch of reasons - from improper RSMail! mailing configuration to server side mailer failure.

Troubleshooting steps:

• We will first have to identify what exactly is causing this - your RSMail! configuration, or your Joomla! installation. You can easily check this by creating a new Joomla! user. As you know, an automated email should be generated with the account details. If the same error is displayed (or the email hasn't arrived to the newly user's email address), then the issue is generated by one of two things:
  • Mailer failure. If you are using PHP Mail (System > Global Configuration > Server), it would be best to contact the hosting provider. As an alternate solution, you could try switching the mailer type to an external service, such as SMTP. More details on the available configuration options can be found here (Joomla! 3.x) and here (Joomla! 2.5)
  • Improper mail settings. In this case, you will have to make sure that you have specified a name and email, within the System > Global Configuration > Server area.

• If the Joomla! user related email worked fine, you should then check your RSMail! Mail Configuration and afterwards, email configuration. Mail Configuration can be accessed from backend > Components > RSMail! > Settings > Mail Configuration (these provide similar details as within your Global Configuration mailer setup).

Next, for all configured emails (backend > Components > RSMail! > Settings > Emails), you will need to check the following fields (where applicable):

• From - should contain a valid email address, or placeholder that is substituted with a valid email address.
• From name - should not be left empty.
• Subject - a value should be specified