Welcome to the MongoDB Community Forums @kommawar_sudheer !
If you are are encountering issues with TLS certification validation please check that your environment’s TLS certificates are up to date as per Keep getting ServerSelectionTimeoutError - #11 by Stennie.
If that information does not help or you need more specific direction for your environment, please start a new discussion topic with details including your language driver & version as well as the specific error message received.
Thanks,
Stennie