Osmdroid and Mapnik tile provider no longer working

Having the same problem as well.

Unfortunately, it seems that osmdroid was banned from accessing http://tile.openstreetmap.org. Reading the tile usage policy, I found these two things which might explain why osmdroid got banned:

Heavy use (e.g. distributing an app that uses tiles from openstreetmap.org) is forbidden without prior permission from the System Administrators.

and

Valid User-Agent identifying application. Faking another app's User-Agent WILL get you blocked.

(osmdroid's useragent is "Apache-HttpClient/UNAVAILABLE (java 1.4)" which is pretty generic)

Please follow Issue 515 to track this issue. We have implemented a fix and we will release a proper update soon.