Could not instantiate mail function error

Every time I try to submit a form I am getting a Could not instantiate mail function. error.

This error can be generated by a bunch of reasons - from improper RSForm!Pro emailing configuration to server side mailer failure.

Troubleshooting steps:

• We will first have to identify what exactly is causing this - your form configuration, or your Joomla! installation. You can easily check this by creating a new Joomla! user in the frontend area. 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), 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.
  • 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.
 
• If the user related email worked fine, then this points to your RSForm!Pro emailing setup. RSForm!Pro generated emails can be configured here: Components > RSForm!Pro > Manage forms > edit the form > Properties. Notice the User, Admin and Additional Emails areas. For all configured emails, you will need to check for the following fields:
  • * From - should contain a valid email address, or placeholder that is substituted with a valid email address.
  • * From name - should not be left empty. The sitename is commonly used.
  • To - should contain a valid email address or a placeholder that is is substituted with a valid email address. A combination of placeholders and fixed email addresses can also be used. If you do use multiple recipients, then the correct email address (or placeholder) separator is comma (,).
  • Subject - a value should be specified