Hi SUZZI-HFO,
Thanks for reaching out. My name is Ali. I'm an Independent Advisor and a Microsoft user like you. I'll be happy to help you out today.
Have you tried to filter out the blanks from your pivot table first column and Right click on the slicer and then navigate to "Slicer Settings". Then check the box that says "Hide items with no data".
Please reply back to us if this solved your problem or ask if you are still facing any problem.
Thanks,
Ali