that looks like a Bonjour issue. Have you tried restarting the router as well? With the introduction of discoveryd the bonjour reliability has really gone downhill.
Is chromecast only limited to local network? With my iphone 6 i can cast to my chromecast at home. I tested at my sister house who also got chromecast, it connects to her chromecast but when playin a file it says Playback failed for "file name" Media failed to load. I can play it on my device good and when i cast it at home it doesnt give any problems.