Can´t import iCalendar Feed

I try to import this RSS feed:

http://www.juoksija-lehti.fi/Tapahtumat/Juoksukalenteri.aspx?&type=data&format=atom&laji=&location=&matka=&culture=&start=19.05.2015&end=24.05.2015&q=

but i get this error message:

The feed appears to be invalid because content not matching the expected format was returned

Why it isn´t working?