Date import SSAS Cube live connection

Hello,

I am connecting live to a SSAS cube with Power-BI desktop (version July 2016). In the cube I created a dimension containing a date (tried different formats like: 2014-01-01, 2014.01.01, 01.01.2014 etc.) with its dimension attribute type set to "Date". Power-BI is not recognizing this dimension as a date since I can't filter it like dates imported from an excel file. Also when I load the data from my cube into Power-BI (no live connection), the columns of my dimension have the data type "text" and I can not change it to "date".

Do my date values have to have a special format or how else can I fix that problem?

Thank you for your help,

Matthäus