Wow Thanks so much for your quick reply.
settings page:
Could not validate App ID. Please try again later.
shortcode on page:
Open Currency Converter Error: No App ID has been setup – please set this in the options screen
I tried disabling wordfence & bulletproof security plugins temporarily just in case, but that made no difference.
It must be something uniquely weird with my settings or my hosting I guess.
I really appreciate your help with this, it’s a great plugin, really.
but hey don’t worry: I can move forward without using the currency converter plugin for now.