Websocket endpoint issue

If my endpoint like this **http://domain_url:4000/graphql**, then everything working fine.
And i changed my endpoint to **http://domain_url/graphql** then i'm facing issue like : "**Could not connect to websocket endpoint ws://domain_url/graphql. Please check if the endpoint url is correct.**" . I'm using centOS for reverse proxy. Is anything needed for graphql subscription ?? kindly guide me for the subscription server setup .

Start by comparing the working endpoint on port 4000 with the failing endpoint behind the CentOS reverse proxy, focusing on the GraphQL subscription WebSocket connection. Verify the subscription server setup and confirm that ws://domain_url/graphql connects successfully through the proxy.

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