The file is not saved

[Goksel12211]

The web server is ok, but when I click the "Save Diagram" button, a pop-up error message appears, stating "Failed to save diagram." Can you please help me understand what I might be doing incorrectly?
The command I tried :
docker run -p 4000:4000 mydraftcc-nodejs-server
Web server is up but when i click Save Diagram button , i got an pop up error with Failed to save diagram. What am i doing wrong ?

[SebastianStehle]

Is there no log on the server?

[Goksel12211]

when i click save diagram , web server throw a error in json : {"code":"EACCCES" , "errno":"-13", "message": "Error EACCES permission denied ,open ''/data/123123....."........

[SebastianStehle]

There is probably a permission missing to access the file. You might need a volume mapping if you use docker.

[Goksel12211]

Thank you for your idea.
I simply removed the line :
USER 1000:1000 in Dockerfile
and it worked.