Youtube S60v3 [extra Quality] -

As YouTube upgraded their infrastructure, they deprecated Flash and RTSP in favor of HTTP Progressive Download and later, DASH (Dynamic Adaptive Streaming over HTTP), rendering the native S60v3 browser incapable of playing YouTube videos natively.

Google phased out the older Data APIs (v2 and v3) that these apps relied on, meaning the app can no longer "talk" to YouTube's servers. youtube s60v3