Passing report parameters in report URL does not work

the documentation in the link below specifies that a filter parameter may be embedded in to the report URL.

https://powerbi.microsoft.com/en-us/documentation/powerbi-service-share-unshare-dashboard/

However, this feature does not seem to be working. I have used this notation on several reports "?filter=tablename/fieldname eq value" making sure that the field and table have no spaces and that the field type is String.

In my specific case the Table name is Sales and the Field is State and I am trying to filter for State = CA using this syntax

?filter=Sales%252FState%20eq%20CA
(or ?filter=Sales/State eq CA )

but neither works