"ConnectionAbortedError: [WinError 10053]" when closing/reloding page

[AimbotNooby]

Hey I've made an website, which sends some date from input text fields to the websocket. The problem is, when I reload or even close the page the following error occurs: "ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine."

Important: The python websocket is running a loop after receiving the message. Without this loop it works.

Btw I don't use the functions set_fn_new_client() and set_fn_client_left(), just set_fn_message_received().

Hope someone can help me with that. Please tell me if you need my code.