Upload works, but Save As fails

(moving this to the correct forum)

Hi all,

I'm quite new to Power BI and have recently set up Power BI Report Server for testing at my organization. I am finding that I am unable to save .pbix reports from Power BI Desktop (June 2017) to the report server. I get the following error message: "Can't open file or folder /. It may have been moved, renamed, or deleted."

Reading the forums it seems that there was previously an issue where users could neither upload nor save reports to the server - this is NOT the issue in my case. I am able to upload .pbix files from my desktop to the server directly, I just can't use the Save to Report Server dialog to do it. I can also open reports from the server in PBI Desktop for editing, but I am unable to save them back to the server. 

I've read through the log file and don't see any errors around the time of saving.

My only clue so far (though this may be a red herring) is that there is a slight mismatch between the report url specified in Configuration Manager and the url that appears when I try to save. The Web Portal URL that I specified is http://[server name]:80/Reports. This is exactly what I enter as the report server address when saving the report, but when it appears on the screen above the error message, another slash has been added to the end (http://[server name]:80/Reports/). That might be expected behavior, but it would at least explain why PBI is looking for a report or file called "/" in the error message. 

In any case, I'm out of ideas for troubleshooting this. Does anyone have any suggestions? 

Many thanks,

Liane