I making survey123 connect customized using app studio. When add Manage Arcgis connections (own portal url), and go to login then show error 400, with message Invaild client_id.
Please help me out for this i already register app with arcgis online as well but does not help.
You are probably using the ClientID from a different Organization account. You need to use or generate a ClientID from the ArcGIS Enterprise that you want to login to, and use it in your custom AppStudio app or custom Survey123.