ADOBE ACROBAT PRO STILL SAYS EXPIRED EVEN IF A BUY IT

I buy a license for Adobe Acrobat Pro and follow all the steps to install it on my MAC but once it finishes installing and I select Launch Acrobat it opens Acrobat window but in the left lower corner it appears the legend EXPIRED BUY NOW in a red circle.

Why is this happening? I buy my license and I don't understand why does is says that.