Fail to 'save web map' in arcgis pro to update existing map in Portal; 'Problems getting data connection for: CIMPATH=.....json

[imansbburg]

I'm trying to update a secure web map that i own on our Portal with more finessed symbology from ArcGIS Pro, but every time it fails. From the logs, the only error line item i see is this:

StatusMessage: Problems getting data connection for: CIMPATH=[long item id string].json

Any ideas?