Problem with viruses

[Pluzdev]

Hello, it seems like the "virus" are invisible. It's very annoying and I don't know how to fix it Can you help me ?

Link of the game: https://agar.lmd.lol

My config file looks like this:

module.exports = {
    host: "0.0.0.0",
    port: 8765,
    logpath: "logger.php",
    foodMass: 1,
    fireFood: 20,
    limitSplit: 16,
    defaultPlayerMass: 10, //default 10
    virus: {
        fill: "#33ff33",
        stroke: "#19D119",
        strokeWidth: 20,
        defaultMass: {
            from: 100,
            to: 150
        },
        splitMass: 180
    },
    gameWidth: 5000,
    gameHeight: 5000,
    adminPass: "DEFAULT",
    gameMass: 20000,
    maxFood: 1000,
    maxVirus: 50,
    slowBase: 4.5,
    logChat: 0,
    networkUpdateFactor: 40,
    maxHeartbeatInterval: 5000,
    foodUniformDisposition: true,
    virusUniformDisposition: false,
    newPlayerInitialPosition: "farthest",
    massLossRate: 1,
    minMassLoss: 50,
    sqlinfo: {
      fileName: "db.sqlite3",
    }
};