Writes that the reference to the object does not indicate an instance of the object, although all values are assigned

Question

Writes that the reference to the object does not indicate an instance of the object, although all values are assigned. I have already tried everything and I have no idea how to fix this error.

public enum blocks
{
    air,
    ground
}

static blocks[][] layer1;
static blocks[][] layer2;
static blocks[][] layer3;
public static blocks[][][] layers;
public static void Start()
{
    layer1 = new blocks[7000][];
    layer2 = new blocks[7000][];
    layer3 = new blocks[7000][];
    for (int y = 0; y < 7000; y++)
    {
        layer1[y] = new blocks[7000];
        layer2[y] = new blocks[7000];
        layer3[y] = new blocks[7000];
    }

    for (int x = 0; x < 7000; x++)
        for (int y = 0; y < 7000; y++)
        {
            layer1[x][y] = blocks.air;
            layer2[x][y] = blocks.air;
            layer3[x][y] = blocks.air;
        }

    layers = new blocks[3][][];
    layers[0] = layer1;
    layers[1] = layer2;
    layers[2] = layer3;
    Player player = new Player();
    Console.WriteLine(layers[1][1][1]); //output: air
    try
    {
        GameMain.text.text = layer1[1][1].ToString(); //error happens here
    }
    catch (SystemException ex)
    {
        Console.WriteLine(ex.ToString());
    }