Previously we've mentioned that Authorize.net is going to stop supporting their SIM solution, and we advised all Catalog users who used the deprecated SIM system to migrate to Authorize.net's new, modern Accept Hosted solution, which requires minimal changes to the account’s configuration.
If you haven't done this yet, we'd like to ask you to take some time and do the changes before January 31st 2023, in order to support paid courses via Catalog. If you stay on the SIM integration, the integration will refuse to proceed to Authorize.net, meaning the payments won't go through.
Please work with your CSMs in order to help you with the migration if needed, they can offer you a migration guide. If you have any questions, reply above, we are happy to help.