I fail to get an accuracy of more than 99%

This is the code that I had

def train(net, loss_fn, train_data, epochs, batch_size):
train_acc= metric.Accuracy()
trainer= gluon.Trainer(net.collect_params(),
                       'sgd',{'learning_rate': 0.1})

for epoch in range(2):

    train_loss = 0

    

    for data, label in train_data:

        with autograd.record():

            output = net(data)

            loss = loss_fn(output, label)

        loss.backward()


        trainer.step(batch_size)

        

        train_loss += loss.mean().asscalar()

        train_acc.update(label, output)

        print("Epoch [%d] Loss:%.3f Acc:%.3f"%(
            epoch, train_loss/len(train_data), 
            train_acc.get()[1]))


net.save_parameters('trained_net.params')

return train_data, train_acc.get()[1]

We are supposed to train for 5 epochs and achieve an accuracy of over 99%

net, ta = train(*get_network(), train_data, 5, batch_size)

The image showed that the accuracy has topped off at 98.8%, which obviously failed to surpass 99%. Plus, the training stopped at epoch[2] instead of epoch[4]

I must have made an error somewhere, but failed to locate that error. Need someone to point out the error