So, you can try to debug the Postman SMTP issue by looking in the log window it has and I think it may have a button to send a test email or something if I remember correctly. You could post over on their support forum. Or, you could uninstall Postman SMTP and install the Custom Sender For Email Before Download, which will let you set the From: of the email (the From: of the email that goes to the address the website visitor types into the form on your website). Then you need to put in a real email address associated with your website in order to get the email to arrive & not get rejected as possible spam by some websites like Yahoo Mail. (This will prevent the email from getting the goofy bluehost system name as the email address in the from:).
On the other problem, which is the red box error message that appears. Like I said, that is a Contact Form 7 error. I don’t know why it’s happening. The email that is being sent is the “notification email” (the email that goes to you, the site administrator, to let you know what the website visitor downloaded). The form that you created in Contact Form 7 has value for the To: and Subject and stuff under the “Mail” tab of the form (if you edit it). Maybe that has gotten messed up somehow? You could try making a new contact form. Actually, your best bet is to probably make a new wordpress page & a new contact form & set it to send the email to you just like your existing form & then take that shortcode & put it in the new page and then test it. Don’t change the shortcode to be an EBD-type shortcode, leave it is as it is displayed so that only CF7 is involved. That way you can test CF7 to make sure it can send you an email and EBD is not involved in any way. If that doesn’t work then you know you have some sort of mail delivery issue or you are misconfiguring CF7 somehow..