Client gets disconnected when display off

[nehalem]

Hello everyone,

I'm running the OpenVPN server 2.6.3-1 under Debian Bookworm on a Raspberry Pi. My clients are a Samsung Galaxy S23 and a Samsung Galaxy Tab S9 with OpenVPN for Android 0.7.5.
I have a problem with my devices disconnecting when I haven't used the device for a while.

I can't see any errors in the server log, but these lines are suspicious:

handy/XXX.XXX.XXX.220:17420 Connection reset, restarting [-1] 2024-04-26 22:25:44 us=692626 handy/XXX.XXX.XXX.220:17420 SIGUSR1[soft,connection-reset] received, client-instance restarting
2024-04-26 22:25:44 us=693213 TCP/UDP: Closing socket

Is there a way to keep the connection even when the device is not in use?

I'm thankful for any help