Error: Connecting to Portal for ArcGIS with Survey123 for ArcGIS returns error message "Invalid client_id"
Survey123 for ArcGIS is unable to login to Portal for ArcGIS 10.3.1.
After entering a Portal for ArcGIS URL, an error message is returned: "Invalid client_id".
Portal for ArcGIS 10.3 and 10.3.1 secured with OAuth2 do not support Survey123 for ArcGIS by default. This is because Survey123 for ArcGIS was released after these products.
Solution or Workaround
Earlier versions of Portal for ArcGIS must be updated to be used with the recently released Survey123 for ArcGIS.
Follow the steps outlined in the following KB article:
HowTo: Add Survey123 for ArcGIS as a registered application to Portal for ArcGIS 10.3.1