Thanks for writing to us. Monetization can be disabled for various reasons. Here's more about it and what to do if it was an error: https://yt.be/help/Be9A . Also, you can reapply for YPP in the next 30 days once you make all necessary changes. Hope this helps.
We'd like to look into it. Just to confirm, have you already appealed the account termination? Also, if you believe your account was suspended in error, here's how you can appeal: https://yt.be/help/7epT . Keep us posted.