Only Flatpak apps can open all websites after connecting to VPN

I'm using PureVPN app (openvpn/udp). Installed via rpm file. After connecting, If I ping youtbue.com it shows:

--- youtube.com ping statistics ---7 packets transmitted, 0 received, 100% packet loss, time 6149ms

but If I ping google.com it will work without any problem.

Some websites work and some not.

If I go to the browsers (Firefox and Brave installed via RPM) they cannot open youtube.com.

Now if I use the flatpak browsers it will open youtube.com without any problem.

I even tried GNOME boxes which is installed as Flatpak and used the same Fedora 34 as host and it will open youtube.com.

What is the problem? how can I fix it?

ifconfig...tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500        inet xxx.xx.xx.xxx  netmask 255.255.255.224  destination xxx.xx.xxx.xx        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 100  (UNSPEC)        RX packets 103978  bytes 135509956 (129.2 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 61682  bytes 4764217 (4.5 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0...

journalctl -fu NetworkManager.serviceMay 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2142] manager: (tun0): new Tun device (/org/freedesktop/NetworkManager/Devices/19)May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2355] device (tun0): state change: unmanaged -> unavailable (reason 'connection-assumed', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2422] device (tun0): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2437] device (tun0): Activation: starting connection 'tun0' (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2444] device (tun0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2453] device (tun0): state change: prepare -> config (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2529] device (tun0): state change: config -> ip-config (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2535] device (tun0): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2559] device (tun0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2564] device (tun0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'external')May 09 20:31:49 fedora NetworkManager[844]: <info>  [1620617509.2585] device (tun0): Activation: successful, device activated.