Cloud SQL external data import into Zoho Sheet giving "Problem in configuring WebData."

Cloud SQL external data import into Zoho Sheet giving "Problem in configuring WebData."

I have a Zoho Sheet in which I have several external data links / imports from Zoho Reports via Cloud SQL / Zoho API.

All was working perfectly when i created it and for a a few weeks after, meaning any changes in the Reports data was correctly reflected in the Zoho sheet.

I noticed today that the data wasn't being updated from Zoho Reports in the Zoho Sheet. When manually updating the external data link, it gives me the error "Problem in configuring WebData."

Absolutely nothing has changed on my end.

What happened here, and how do I avoid it in the future?