IThis is specific to the Get Data UI.
I could connect to SQL Anywhere 16 using the Sybase Databases in the Get Data menu.
http://hodentek.blogspot.com/2015/02/powerbi-preview-reporting-from-sql_13.html
Power BI is updated to the August Version and SAP has updated there SQL Anywhere to Version 17.
When I try to connect to SQL Anywhere 17 using Get Data this is the screen that comes up:
Clicking OK should normaly bring up an authentication screen. Although it does it sometimes more often it seems to bring up a cached message side stepping the authentication altogether. The screen that follows makes no meaning.