I have encountered a problem. I have followed this tutorial (https://goethereumbook.org/en/event-subscribe/) in goethereum, but when I replace node endpoint matic(wss://rpc-mumbai.matic.today), I encounter this problem.
ERROR: websocket: bad handshake (HTTP status 503 Service Temporarily Unavailable)
My contract is on Mumbai matic network, this address is 0x6d66A45b628A7B497B618FA637F77a47Ab1E8943
Thank you for your help
