Amazon strictly controls which e-books can be accessed on Kindle e-readers and doesn’t allow cloudLibrary to lend e-books to most Kindle e-readers, except for the Kindle Fire. You can email kindle-feedback@amazon.com and request that Amazon allow compatibility with cloudLibrary books.
All Pennsylvania residents are eligible for a digital library card through the Free Library of Philadelphia, which provides access to Libby, an app whose e-books are compatible with Kindle Paperwhite. Bucks County Free Library has no affiliation with the e-book collection offered by the Free Library of Philadelphia and cannot offer troubleshooting for Libby.