Unable to send but can receive. Error message in text!

Unable to send but can receive. Error message in text!

Not sure why, just happened out of the blue. Had been able to send earlier in the morning and then it just stopped. Please help!

 Sending failed; Reason:Could not connect to SMTP host: smtpout.secureserver.net, port: 25, response: -1. Your Mail has been placed in outbox for retrying

Thanks!!