[solved] Pico as http server: "Uncaught Error: > not registered"

Hi,

I am still trying to have my Pico+ESP8266 act as simple HTTP server. It has been working last week (inconvenient of having this only as a hobby project :/ ) but now I keep getting this error.

I used http://www.espruino.com/Interactive+Web+UI to kick start my code. It still is pretty close to it. The first request I make works, but the second always triggers this error:

Here, as seen in the Web IDE's console:

GET /
GET /
ERROR: Socket error -1 while sending
Uncaught Error: > not registered at line 2 col 64 ...Error(key+" not
registered");
^
in function "unregister" called from line 7 col 26
at.unregister('>');
^
in function "callback" called from line 4 col 40
if (callback && (n=callback(d))) {
^
in function "lineCallback" called from line 29 col 27
lineCallback(l);
^
in function called from system

Code:

var wifi;

function connectWifi(){
  
  Serial2.setup(9600, { rx: A3, tx : A2 });
  
  wifi = require("ESP8266WiFi").connect(Serial2, function(err) {
    if (err) throw err;
    wifi.reset(function(err) {
      if (err) throw err;
      console.log("Connecting to WiFi");
      wifi.connect(WIFI_NAME, WIFI_PASS, function(err) {
        if (err) throw err;
        console.log("Connected");
        // print IP address
        wifi.getIP(console.log);
        // Create a server
        require("http").createServer(pageHandler).listen(80);
      });
    });
  });
  
}


function pageHandler(req, res) {
  console.log(req.method,req.url);
  if (req.method=="POST") {
      res.writeHead(200);
      res.end('POSTHOME');
  } else if (req.method=="GET") {
    if (req.url=="/") {
      res.writeHead(200);
      res.end('GEThome');
    } else {
      res.writeHead(404);
      res.end("404: Not found");
    }
  } else if (req.method=="OPTIONS") {
    if (req.url=="/") {
      res.writeHead(404);
      res.end();
    }
  }
}

connectWifi();

I spent several hours looking for the origin of the error, as well as its cause with no luck. Does someone recognise it?