There is a bug in socket.io-client version 4.8.1.

[khadem-mh]

When the connection between the client and server is established for the first time, everything works fine. However, as soon as the user goes offline and the socket.io-client attempts to reconnect between the client and server, there’s no issue up to this point. But the problem occurs when the user comes back online. In this case, an HTTP request is sent, but the middleware doesn’t execute, and the connection event is triggered directly. If there’s an authentication middleware, it won't be executed, causing the program to break. Both the server and client versions being used are 4.8.1. However, I didn’t encounter this issue with version 4.0.1, which I tested on the client side, and the program didn't break.

[wes337]

I think this is the same bug as #5197

[darrachequesne]

@khadem-mh could you please detail your environment? Do you use the bundle from the CDN? Else, which bundler are you using?