Just to also add we are experiencing the same issue with order creation. It's happening across a number of independent sites. No change on our side. We've retried recycling API keys. It looks like order creation is failing across all SquareSpace stores for us.
We've replicated by just trying to place via a CURL request to eliminate the possibility of a code regression and it still occurs. Even with full permissions on the API key.
It's causing significant disruption to our merchants.
{
"type": "AUTHORIZATION_ERROR",
"details": null,
"message": "You are not authorized to do that.",
"subtype": null,
"contextId": "EGRESNIEPLIZAUSQUEYQ"
}