Hey @Avhijit-codeboy,
First, Welcome to the community! 
Glad to see you made a post here, When I got up this morning and was able to get through all the emails I found yours and replied. Let me copy that over here, as we will need some more details to be able to help you at all.
"Not sure, this could be for a number of reasons. The best place to get answers to your questions is our community forum: https://discuss.streamlit.io/ (you might even find an answer to your question before you ask it!)
When you post to the community, make sure to follow the guidelines here: Welcome ! Some suggestions for your first Streamlit question
At a minimum, add the link to the repo you’re trying to deploy from and the error logs from when you tried to deploy your app. Without these things, it’s nearly impossible to help troubleshoot!"
Happy Streamlit-ing!
Marisa