When creating a website based on Action Cable, "was interrupted while loading the page" error occurs in Firefox

I am creating a network outlet using a rail control cable. It works well when deployed to localhost - my dev env. But when I publish my project in Geroku. Some strange things happen. Woesocket also works well in chrome and safari. But in firefox I got this error information in the console.

Firefox cannot connect to the server at wss: //someapp.herokuapp.com/cable. The connection to wss: //someapp.herokuapp.com/cable was interrupted while loading the page.

I read Todd Wolfso's solutions

This is my security.tls.version.max config in firefox. security.tls.version.max

I cannot fix this. On local I am using http and heroku using https!