“Could not instantiate mail function.” What’s that?

This generic error message is when your host has issues sending your emails.

It's rarely permanent, and it's usually due to one of the reasons below.

We recommend our users to contact their host if this issue persists.

If it can't be solved by your host, we usually recommend sending from a professional provider.

Based on our experience it can be:

  1. you are on a local server (localhost)
  2. recipient's email address is invalid
  3. there's a special character in the subject
  4. there's a special character in the sender/receiver information
  5. the subject line is too long
  6. the bounce address you specified is not accepted by your server
  7. you already sent too many emails

1. You are on a local server (using WAMP for example)

This kind of web server does not have a mail server so you can't send emails from your local server.

Solution: send with an external SMTP server instead.

2. Your receiver email address is not valid

Your mail server may refuse to deliver your message if the receiver email address is not a valid one.

If you have " could not instantiate mail function" for only a few of your subscribers, it may just be because their email address is not valid!

3. You included a special character in the subject line

Some mail servers will refuse to deliver your message if it contains special characters in the subject such as a quote or a comma or any other kind of special character (ù,ï,ä)...

Solution: create a new newsletter, specify a standard subject line ("test" for example) and give it a try.

4. You included a special character in the sender/receiver information

The same way, some mail server will refuse to deliver your message if the sender information contain special characters.

Solution: remove special chars from a single subscriber to see if that solves the issue.

5. Your subject line is too long

Some mail server may not authorize you to deliver your message if the subject line is too long.

Solution: shorten your subject line to a single word to make sure it's not a problem of subject length.

6. The bounce address you specified is not accepted by your server

Some servers won't accept to deliver your message if you specify a bounce email address.

Others will force you to apply a bounce address which belongs to your own domain. Tricky!

Solution for free: leave the bounce address empty in MailPoet Settings > Advanced and try again

Solution for Premium: leave the bounce address empty in MailPoet Settings > Bounce Handling and try again

7. You already sent too many emails!

Most of hosting company have daily or even hourly sending limits.

Solution: see sending limits per host or contact your host directly to find out your sending limit. Then, adapt your sending frequency in MailPoet Settings > Send with...