Error when sending email

I have setup an Email Account and successfully sent a test email. However when I place an order I get an "Error sending e-mail. Failure sending mail." error.

Would anyone know what could be happening?

Thanks

There is a Scheduled Task running in the background which is having an error sending emails
See yourwebsite.com/Admin/ScheduleTask/List - Send Email

Check your settings

Search the forum for problems other users had

https://www.nopcommerce.com/boards/search.aspx?searchterms=error+sending+e-mail