Why does VPN drop mostly on the phone?
iOS and Android can limit background connections, especially with low battery, battery saving or frequent network switching.
Connection drops
VPN keeps disconnecting: how to stabilize it
If VPN turns on but drops after a few minutes, the cause can be battery saving, network switching, aggressive Wi-Fi, mobile filtering or an old profile.
Common causes
the phone limits the VPN client in the background
the device switches between Wi-Fi, LTE and 5G
the ISP breaks long TCP connections
the client uses stale subscription parameters
What helps
1
Allow the VPN client to work in the background and disable battery saving for it.
2
Refresh the subscription and reconnect.
3
Test the second profile, including Hysteria 2 if it appears in the client.
4
Compare behavior on Wi-Fi and mobile data.
Common questions
Do I need to keep the app open?
Usually no, but the client needs background permission and a system VPN profile.