I'm using this library on a Pi Pico W (Arduino IDE / C++) to connect using socketIO to a Node.js Socket.IO server.
This is working well when I connect to the root namespace. The Pico connects, and I can emit messages which I receive on the server end.
However if I connect to a different namespace, the socket disconnects and reconnects when the Pico tries to send.
i.e. when I have:

void socketIOEvent(socketIOmessageType_t type, uint8_t * payload, size_t length) {
...
 case sIOtype_CONNECT:
 sprintf(tmps, "[IO] Connected to url: %s", payload);
 dbg(fDebug, tmps);
 // join default namespace (no auto join in Socket.IO V3)
 socketIO.send(sIOtype_CONNECT, "/");
 smsg(SMSG_SCNCT);
 break;
...

I can emit messages to the server.
But if I change the namespace from "/" to "/timer"
i.e.
void socketIOEvent(socketIOmessageType_t type, uint8_t * payload, size_t length) {

...
 case sIOtype_CONNECT:
 sprintf(tmps, "[IO] Connected to url: %s", payload);
 dbg(fDebug, tmps);
 // join default namespace (no auto join in Socket.IO V3)
 socketIO.send(sIOtype_CONNECT, "/timer");
 smsg(SMSG_SCNCT);
 break;
...

I can successfully connect to the /timer namespace. From the Node.JS end I can see the socket connect. However as soon as the Pico emits a message, the socket disconnects (Socket.IO in Node,js reports error reason "force close"), and the Pico then connects again.

It is possible to use namespaces other than root with a Pi Pico W? The last comment in issue #620 (back in 2021) suggested the namespace is not being saved?