Excel Data is not shown in the Data Field

Hi there, 

I am currently working on a  report based on a import query from a database. 

I do needed to add a excel to the report, weirdly though I can import it and can work with the data in "Edit Queries" and in the report itself.
But in the Data Tab nothing is showing up, therefore I can´t establish any relationships as it shows no data. 


I tried refreshing it, deleting the table again and uploading it again, copying the code into a new blank querry, but nothing helped. 

Anyone has experienced this bug before?

Thanks for the help,
Johannes