TopHat Map-All fasta inputs were empty

I am a beginner with Galaxy and trying to use TopHat to map my sequence with the ref genome from UCSC, I don’t konw what’s wrong with it. I try to transform the data format. But it still didn’t work.
The waring like this


but the ref genome from UCSC is not empty


Can anyone say what is the problem and how to rectify.

Thank you