Tensorflow-GPU Error: "RuntimeError: CUDA runtime implicit initialization on GPU:0 failed. Status: all CUDA-capable devices are busy or unavailable"

I am using a GTX-1660Ti on training a Convnet. I was able to use my GPU to train 3 weeks ago. Today, I tried training my model and ran in to the following error.

RuntimeError: CUDA runtime implicit initialization on GPU:0 failed. Status: all CUDA-capable devices are busy or unavailable

When I run,

tf.config.list_physical_devices(device_type='GPU')
print("Num GPUs Available: ", len(tf.config.experimental.list_physical_devices('GPU')))

I get

[PhysicalDevice(name='/physical_device:GPU:0', device_type='GPU')]
Num GPUs Available:  1

When I run

import tensorflow as tf
if tf.test.gpu_device_name():
    print('Default GPU Device: {}'.format(tf.test.gpu_device_name()))
else:
    print("Please install GPU version of TF")

I also ge the same RunTimeError.

I'm not sure why I'm getting this issue when it was working fine couple weeks ago... Anyone have similar issue? I have tensorflow-gpu installed and my tensorflow.version is '2.2.0. I'm also using Ubuntu 20.04 on WSL