WebHDFS return error 404 in random when I open the file on hdfs

[#1]

I am willing to open a file on hdfs via WebHDFS. As I cannot access the redirect location of datanode, I set a proxy to access it. However, I find it sometimes return the correct file content, but sometimes not. Instead, it returns 404 error for "Problem accessing {Path}", and I cannot find any rule, just like in random.

How to resolve it? Thank you.