Unable to Save Dashboard on ArcGIS Enterprise 11.3 site

[DfIRivers]

On our ArcGIS Enterprise portal I have a number of Dashboards.  We recently upgraded to Enterprise 11.3, and most of the Dashboards still open, and I can make changes and save again.  However I have one Dashboard which when I open to Edit, it immediately has a blue dot beside the [Save] button.. as if the Dashboard had an edit that hadn't yet been saved.

When I hit the [Save] button nothing happens.  When I try [Save As], I get a message saving "Could not save. Verify your credentials".

Apart from re-building the Dashboard from scratch, does anyone have any advice as to how to get my problem Dashboard to Save?

[DavidSolari]

If you hop in the ArcGIS Online Assistant are you able to extract the dashboard's data? Worst case this'll make it easier to rebuild it.

[Eugene_Adkins]

Complete shot in the dark, but do you have another user with credentials that can log in and try to save it?

[DfIRivers · Accepted solution]

Thanks for the suggestions.. I ended up re-building the Dashboard as was still able to open the problem Dashboard and refer to it during the re-build, so all working again. 

Then I had the idea of trying removing the Date Selector from my problem Dashboard and it then allowed me to save it again!!  So the problem seems to have been with the Date Selector widget all along.