excel link to access query not working
 

In Excel 2007 I have used the "get external data" function to link to an
access database query. However it comes out blank in Excel (the header row is
there but no data). Table, pivot chart and pivot table are all blank. The
query is OK in Access. If I instead link to a table in the same Access
database this works (i.e. I see the data).

What's going on? The query isnt very complicated, it just joins three
tables together. It has an expression and a couple of criteria (Like "yes*")
but that's it.