I have an ArcGIS enterprise portal, and w published a survey123 form on it, and a make a collaboration between this portal and ArcGIS online account and ishare this survey with this AGOL, but when i tried to create a survey123 from existing feature in AGOL Account i can't and this error will appear.
Portal: Survey123 form-- collaboration-- share this layer with the collaboration group
AGOL: trying to create a survey from existing feature service-- Error
Based on the error message it seems like the feature service was shared as reference and not copied to the ArcGIS Online environment.
What's likely happening is Survey123 is passing along your ArcGIS Online token to the service, but since it's likely still referencing your ArcGIS Enterprise service the ArcGIS Enterprise organization is rejecting the ArcGIS Online token.
One way to confirm is from the item details page for the ArcGIS Online item if you scroll to the bottom of the page there will be a REST URL. If you select that REST URL does the URL point to ArcGIS Online or your ArcGIS Enterprise Organization?
If you share the feature service as a copy and it creates a new hosted feature service in ArcGIS Online that should work, or if you need it to point to the feature service from your ArcGIS Enterprise Organization I would suggest not sharing it through the collaboration but adding it as an item to your ArcGIS Online organization and storing the credentials.