Customers are getting "Error: unable to send email. $smtp_host may need to be set." when they try to get their password emailed to them.

but...

The SMTP host IS set in the config file and customers and my admin account ARE getting order confirmation emails.

Where do I need to look to see why password reset emails are failing? This might be a new issue since I upgraded to 2.6.0 as I've never had this complaint before.