Failed to upload file in Wiki

I want to use the wiki feature to manage documents, but when I create an Open Wiki and create a page, I cannot attach files. It always returns a 403 or 404 error. What should I do?

My version is GitLab Community Edition [11.10.0]

Project visibility is private, it returns 404 when i attach a file:

Project visibility is public, it returns 403 when i attach a file:

Could someone help me? Thank you very much