Show some respect, humanity is the key.
Gain some expertise or invite a person who could address the technological questions. Not only this will help you ask about a candidate's coding skills but it will show that the company has a clue about what the duties are supposed to be fulfilled. This will make you be on the same page and feel equal between each other, rather than being viewed as a rigid overseer.
Also, regardless of the verdict, don't create a vacuum leaving the candidate with no result - the world, especially in a digital realm, is a much more tight space than you may think, leave your reputation clean to approach tens or hundreds of candidates further on. No matter how much the devs value hard skills, your decency, humanity, and respect will be appreciated.
Descending to visiting interview could also be a great move, especially if it's about the executive positions. Sure, you can't always be there but the SMBs proved to benefit from this move a lot.