How to play iTunes library songs via Alexa voice control

Exact same problem. Hoping there is a solution soon, or my Amazon Dot will collect dust.

Local library support has significant technical challenges that are not present with Amazon supported services. Specifically, Alexa would need direct access to your local index, or have a copy of your index in the cloud, neither of which Alexa can do today. In the meantime, you can initiate play from the Sonos app and then use Alexa to control the playback and volume, and even ask what's playing. There is also the option to upload your library to Amazon for $24.99 per year, then access it via Amazon Music on Alexa and Sonos.

That's totally worth it - going to figure that out now. Thanks!

That's totally worth it - going to figure that out now. Thanks!

See this link:

https://www.amazon.com/gp/feature.html?ie=UTF8&docId=1001432841

Amazon discontinued this service 1/15/2018

Further to Beeper's comment, page https://www.amazon.com/gp/help/customer/display.html?nodeId=201379330 gives details of Amazon's change in policy. Basically, if you bought content from Amazon, you can host it on Amazon's cloud. if you didn't buy it from one of their services, you can't store it in their cloud. If you're an existing subscriber, what you have (either the 250 song free service or 250,000 song paid subscription) will persist until you fail to renew, at which time the facility will cease to be available and your songs will be removed.
It seems a bit harsh, and makes me incredibly grateful that I opted for iTunes Match when I was trying to decide which route to take! Amazon's rationale is that this is being done because everyone listens via streaming (so nobody needs to own content any longer), but the fact is that I can't be alone in owning obscure music that isn't available from any streaming services, and if I'd relied on Amazon, that content would no longer be available.
Needless to say, though, I'll be downloading all my iTunes Match stuff to external flash drive in preparation for Apple issuing the same edict...

I have met the same situation. So I searched this reason why this issue happened on Google. Got the answer, such as one stuff, called DRM. Anybody knows it?
It recommends me to get an Audible converter like https://www.drmare.com/drm-audio-converter-for-mac
Unfortunately, it's paid! So here, there is a solution to solve this issue soon?

Just got the Sonos One with Alexa. I am so disappointed that it is going back.

You can do this using a third party Skill, but the standard Sonos skill cannot due to the way it is architected: it has no local network access which prevents access to playlists and most of the music services that Sonos supports.