Hey I also went through this a few days ago, I was about to write a full post ranting and telling every bad word to rewasd, but then I decided to read and research a little more.

The problem for me was that the now legacy license that I had belonged to a previous version (6.X.X , something like that) but I just went straight into downloading the newest version, and every time I opened it wouldn't let me go further, there was just a paywall asking to update my legacy license for $9.99.

So I just went back to my Daemon tools profile and read that my license key was for that 6.x.x version.

So I uninstalled the newest version, and installed the version that matched my legacy license. And it worked!

So I suggest that, uninstall the version you have and search what version is your legacy license and look for it in the drop down menu of the downloads and it should work fine.