So I've made a browser form in InfoPath 2013 to be used to request new space for employees. This first goes to the appropriate office manager at the appropriate branch location before being sent to the Maintenance department to set up new desks or whatever.
I've got a list in SharePoint Online that I've been using as reference for many forms that lists Site Name, street addresses, phone numbers, and front desk emails for our different branch locations. My form populates a drop-down list with these branch names from this list via receive data connection and another field with the front desk email address. The first submit action saves the filled out form in the same form library it's published too. I've promoted the field with the branch's email address to a column in SharePoint (LocationEmail)
I created a very simple workflow in SharePoint Designer 2013 (this is a 2013 workflow) that just sends an email with a link to the form in the library. This email goes to CurrentItem:LocationEmail. Only it doesn't go there. It goes nowhere. My workflow gets suspended with this error:
The e-mail message cannot be sent. Make sure the e-mail has a valid recipient.
I go back and add my email in the CC field and the workflow completes and I get an email and see the To: field is blank. I put the same value CurrentItem:LocationEmail in the body of the email and it returns the correct email address.
This an internal address. I tried a 2010 workflow though, just in case. I worked with Microsoft's SharePoint support people who spent a good couple hours on it with me. They said it was probably something with InfoPath and they don't support customized workflows.
I'm pretty sure InfoPath is fine, the value that shows in the promoted column in the form library is exactly what I want and is in a valid email format (email@example.com). These addresses are actual domain user accounts and not distro groups...
Doing a mail trace in Exchange for sender: firstname.lastname@example.org shows no attempts to send it except for successful delivery to me when I'm CC'd.