Error to upload a a file "Empty Response"

Dear all,
I have a problem when i want to upload or drag a file into a workspace.
The message error is: “Empty Response”. Some idea??
It is strange because was working well but suddently this message appeared and cannot upload anymore.

The version of the Pydio is the latest one (Version : 8.2.2)
I’m using CPanel with PHP 7.1 (ea-php71) version

Thank you very much in advance

What is value of output_buffering ? It should be “Off”