I'm using iPhone 5s / iOS 9.2, and my computer is running Windows 10. I have the new Chromecast with the floppy cord. Every device is on the same wireless network.
Guys, these were never problems a few months ago. Now, it happens literally every day. This is one of the most frustrating bugs I've ever encountered, and for an app I pay for this is extremely vexing. I don't recall if it happened after an update or not.
I'm going to leave Spotify soon if this isn't resolved. Can you imagine it taking 5 minutes of activity to cast your music to your TV? So annoying it's pointless.
Also, for what it's worth, I haven't noticed this problem with other apps.