Lately I have been receiving this #550 error message. Can someone tell me why I might be getting them? The e-mail I send never gets through to the recipient when I get this message.
This is a SMTP error from your ISP. It indicates that your message is being rejected by a server. There can be a number of reasons this might happen. Is this happening with all of your sent messages, or only those going to one recipient? Are you getting any explanation of why the message is not getting through? You should check with you ISP about this.