Unable to queue music in web player behind cloudflare

[shikasta]

This one was a bit confusing. Initially I couldn't work out why I was suddenly unable to queue or play tracks in the webplayer by pressing any of the play or queue buttons. Eventually I remembered that I had enabled CloudFlare for the entire domain (to take advantage of the free veriffied SSL rather than my self-signed certificate). Once I disabled it again for the subsonic subdomain of my server, I could once again queue and play tracks.

The original problem was hard to identify as nothing was showing up in server logs; now I know that it'll be in CloudFlare's server logs instead, sigh. I could navigate the entire web interface without a problem and popup messages were displayed but none of the queue buttons worked. Does anyone have any idea what it would be that was being blocked here and maybe how to fix it (I'm willing to test things)?

I'm running Subsonic 5.1 behind Apache 2.4.7 on ubuntu 14.04.