I have the exact same problem. WordPress in general can send emails, but when a user request a quote, they get an error. The request is however saved to the “Price Requests”-page in the admin console, and I can edit it, and send a quote. That quote-mail is sent successfully. I have set the same email in Settings and Email Templates.
Another weird thing is that the “Check & Log Email”-plugin reports these “Price Requests”-emails as failures in the UI, but if I export the email-logs, it says Status=Success for them.
