The export_map function in ArcGIS API for Python fails and returns the following error message, "Error 400: Invalid URL" if the Portal uses a custom print service as the default.

Workaround

Change the value of 'gis.properties.helperServices.printTask.url' property to the REST URL of the out of the box print service. For example:

gis.properties.helperServices.printTask.url = https://server.domain.com/webadaptorname/rest/services/Utilities/PrintingTools/Export%20Web%20Map

Steps to Reproduce