[solved] Mailer Error: Could not instantiate mail function

Error is:
Test emails work fine and so do small batches, but full lists (50+ users) report the following error in the eventlog shortly after queueing a batch:

Quote:
Mailer Error: Could not instantiate mail function

The Reason:

Bluehost limits email to 50 messages per hour by default. Once this limit has been exceeded, the above error is produced in the PHPlist eventlog after each individual message is sent. You can verify this by looking at your server error logs; it will likely state that the hourly email limit has been reached.

The Solution:

You’ve got two choices:

Throttle your email below the acceptable limit (50/hour). Keep in mind that your regular email traffic must be considered as well. If you send 50 list messages per hour, you won’t be able to send your normal email for another hour either.

The other solution is to contact Bluehost and request that the limit be increased–there’s no guarantee that they will, but it could be worth a try. Don’t bother doing this if you are using PHPList to spam unsolicited messages–it will just get your account terminated.

Although my experience with this issue has been limited to Bluehost, there’s no reason why this error wouldn’t apply to other hosts. When in doubt, check your server’s error logs for more details.