What is this 500 error?

I have just published an article-https://medium.com/@oce_/%E8%87%89%E7%9B%B2%E7%97%87%E7%9C%8B%E9%9B%BB%E8%A6%96%E5%8A%87%E7%9A%84%E6%97%A5%E5%B8%B8%E5%9B%B0%E6%93%BE-%E9%9B%B6%E5%8A%87%E9%80%8F-c62e29e8480e

and received claps from someone too:

But it shows 500 error a few minutes after and I can’t view it. I didn’t back up the article…. Did anyone experience this before? I spent a lot of time…