Authorize.net reports that they have successfully mitigated the issue they reported earlier. On our end, we can confirm that credit card transactions appear to be working normally again on IndieCommerce 1.0 sites. We will continue to monitor the situation.
https://status.authorize.net/
Credit Card Processing Issue Acknowledged by Authorize.net
The Authorize.net payment gateway that is used by IC 1.0 stores to process credit card orders is experiencing a service disruption. They are in the initial stages of investigating. We will provide additional updates as they make them available.
For more information, see their status page: https://status.authorize.net/
We will continue to investigate from our end to see if we can identify a workaround.