Since early April, Microsoft has disabled Office 365 authentication for external clients connecting to Dataverse in all Power Platform environments. The discontinuation was already published two years earlier, read here.
If you experience problems connecting to external clients and tools in your Dynamics 365 system, such as Documents Core Pack or Resco Mobile CRM, you can find the relevant vendor blogs on switching to the new OAuth2 authentication here.
Resco:
Documents Core Pack:
Our tip: If you use other add-ons, search specifically for the name of the product together with the search term "OAuth2". Do you need support with the conversion? Then please contact our Dynamics 365 team.
TSO-DATA GmbH
David Eggenhofer
dynamics365[at]tso[dot]de
+49 (541) 1395-707
