u/Extension-Log-4139

I've had this Kindle for years, it was a gift from my father before a deployment, so I don't want to just toss it. I have, for the first time, run into the below popup, refusing to allow me to download recently purchased ebooks from the kindle library onto the device. Is there a workaround? Is this a calibre kind of fix? Is there any way to make this device usable again? Can I load the ebooks directly through a PC?

Kindle is model No. EY21

Thanks