I keep getting messages in Entries that have a “YES” under the Spam heading. But when I Hover over the entry, it has an option to “Mark as Spam.” So I can’t see how to tell Gravity forms that this is NOT spam. How do I do that?
It sounds like your form contains a field labelled “Spam”, and the value of that field in the entry is “YES”, and you are viewing that entry in the default “All” filter view, which is where the “Mark as Spam” action is available. The “Not Spam” action is only available for entries in the “Spam” filter view, but it wouldn’t change the value of your custom “Spam” field.
You could use the gform_entry_is_spam filter to set the entry status, during submission, to spam if your custom “Spam” field contains “YES”.