And yet I think I've got it. At first I things weren't even getting to the email gateway. So I may have fixed the issued by moving the media assets to the new location (I can edit the template and save it just fine now with all my custom images intact). But our email gateway was rejecting the From address which is what generated the "cannot send profile email" message.
But I do have a question...the gift card "coupon" doesn't get created unless the Email goes out? It would be nice if it would generate the gift card with the purchased balance/amount so we could manually re-send the voucher later. Am I missing something?
Also, the gift message was not showing up as well as the Recipient name as it did before the upgrade. So if anyone else is using this with the same result, check your email template ... the fields in Hikashop will need to be placed in the template again. There also appears to be a new option, From so you may wish to add a new custom field in HK to take advantage of this.
So I think I've fixed or found solutions to my issues, mostly related to updating from the 2.x to the newly licensed 3.x version.
So now I just have one issue I need to resolve. The image for the Gift Card is embedded in the HTML email using a CID tag. But it references an object that doesn't exist in the email payload. The gift card image is usually an attachment named like "15441547081241447980.png" but the html code that replaces the template tag {image_embed} is always replaced with "<div><img src="cid:couponimageembed1"></div>" ... and couponimageembed1 doesn't exist so we get a missing image icon in the email. The PNG is attached as a normal attachment, outside of the HTML email message.