Error message : "Class 'lib\App' not found"

Hi, I am getting the following error.

{code: 0,…}
code: 0
file: “/home/–/public_html/dmxConnect/api/test.php”
line: 5
message: “Class ‘lib\App’ not found”
trace: “#0 {main}”

The server action is working well in local but not in remote
Regards