These are two reasons why the integration is failing after migrating from Classic Knowledge to Lightning Knowledge. The URL formats for articles change when migrating from Classic Knowledge to Lightning Knowledge, so any integration that relies on URLs needs to be updated accordingly. Also, users need to have Modify All permission on the article type object to delete archived articles in Lightning Knowledge, whereas in Classic Knowledge they only needed Delete permission on the article type object. Verified References: :
URL Formats for Articles Change When Migrating from Classic Knowledge to Lightning Knowledge : Delete Archived Articles in Lightning Knowledge