Adding a Metric value results in "Server Error"+issues

Sebastian Jekutsch+CSR Report Available.

I opened the "values needed" list and grabbed the first one in the list, Hitachi, opened the Metric Progress of Hitachi and (1) cliked on "+ Add New" (see screenshot at "1").

 

 

 

 

A dialogue popped up, I added Year 2014, Value "Yes" (which supposed to be "yes") and a URL to a source. After clicking ok, a "Server Error" was reported, see screenshot.

Note that

 the URL is already linked to the Source  Page_000001485.

 

 Browser IE11.0 (x64)