Amazon fire,10

Hi,

See this thread: https://community.adobe.com/t5/acrobat-reader-mobile/can-not-read-pdf-files-in-cloud-using-kindle-fire-hd-7-error-the-document-path-is-not-valid/td-p/10711784?page=1

The solution posted by wtfturtle at the end of the thread seems to be what you're looking for.

NOTE: Just be aware that both methods offered in the thread,  lie rooting an Android device and/or enabling "Apps from Unknown Sources" and "Android Debug Bridge (ADB)" gives access to all applications in your devices and may compromise all of your data.

Make sure that you know what you're doing when using these advanced features.