When you say you have the rights to it, you might only have the right to read it, not to give it to anyone else. What was the license text when you bought it?
It seems like Hoopla does a lot of self-published and indie published books. That kind of fits in with their business model where they charge a flat fee per lending of the book, so they have an incentive to get as many books on the platform as possible.
When you say you have the rights to it, you might only have the right to read it, not to give it to anyone else. What was the license text when you bought it?