Have you tried sudo dnf upgrade --refresh in a terminal.
Welcome to the forum @rahulchukkath . Please take a look at the introductory posts in the #start-here category if you’ve not had a chance to do so yet.
Assuming your internet connection is working fine, for gnome-software/Discover, which are both packagekit based, try:
pkcon refresh force
then restart gnome-software/discover.
Thanks brother. This worked <3