Hi @Faisal Kabeer ,
please check the routing table of your Azure VM.
There should be a route to the "client network" using the VPN Gateway connection.
Also verify the routing in the "client network". There should be a route defined that points to the Azure VM subnet (172.20.0.0/24).
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten