Ah, I see! I hadn’t done the Authentication part, because I didn’t realise that the Authentication screen reveals new options/controls/information after the API Key has been configured. When I first installed this plug-in, I went through all the menus just to look at what options/settings there were, and I figured there was nothing relevant on the Authentication page regarding Smugmug, because the helper text tells the user to head over to Photonic -> Settings -> Smugmug. So I never bothered to check there after I’d entered & saved the API key.
There’s nothing to suggest that the Authenticate page will reveal new fields once the user has entered their API key – can I suggest a minor tweak to the helper text on the Photonic -> Authenticate -> Smugmug section, something like “Authentication Options will not appear until you have successfully configured API Key and Secret at Photonic -> Settings -> Smugmug”.
Thanks for your quick help, stoked that this is now working 🙂