First, I got an email saying that I had a video that violated community guidelines/terms and conditions. Then five minutes later, I got another email saying that due to repeated violations, effective immediately, my channel was suspended/terminated and that I would not be allowed to have my channel reinstated for a minimum of 6 months.
I emailed them numerous times trying to get it figured out, and offered to make whatever changes I needed to make--and they kept telling me it was under review.
My community began emailing them like crazy, and long story short, they finally sent me an email saying it was a mistake and that I had done nothing wrong and didn't need to fix anything. (Frankly, I think my channel was "channel bombed" by trolls.)
LOTS of lessons learned in that experience! The big one being that I needed to backup all my videos, and put them on vimeo in case this happened. (I only recently started saving my videos, as all my earlier ones were uploaded from my iphone and then deleted.)