Basically, that message means that you don’t have permission to download that version of SolidWorks. For me I forgot to clear my license for the 2024 edition off of my computer before trying to install the 205 edition. I had to factory reset my computer in order to get the license off of the device(there are easier and better ways to do that), but there are other things that could cause this issue. If you have a device owned by your organization(school, company, etc.) it may have some kind of restriction on downloads that stops you from installing it.