WebSocket Error in OnlyOffice - 502 Bad Gateway

I am experiencing an issue when trying to load documents in OnlyOffice. The DevTools console shows WebSocket connection failures with the following error:

WebSocket connection to ‘ws://127.0.0.1:8888/…’ failed
Failed to load resource: the server responded with a status of 502 (Bad Gateway)

Additionally, multiple requests to /socket.io/ also return the 502 Bad Gateway error.

The server is running locally on port 8888. Has anyone encountered this issue before or has any suggestions for a solution?

Hello @emanueldev,
Please specify if you are using a reverse proxy in front of the Document Server, if yes, please specify which one

I’m using Nginx