Microsoft deprecated the WS Trust protocol for Microsoft Dynamics CRM and MSD CRM Online. Effective in 10.5.2, you must use the OAuth authentication for the passport authentication type to access Microsoft Dynamics CRM Online.
After you upgrade to 10.5.2, mappings fail when you use the password authentication type without the client ID and client secret to access Microsoft Dynamics CRM Online. You must update the Microsoft Dynamics CRM connection to OAuth and use the CRM Organization web service URL.
You can continue to use the Claims-based and Active Directory authentication types to connect to the on-premise Microsoft Dynamics CRM.