Посмотрел логи... Ситуация странная.
Действительно каждые 4 минуты соединение отключается. Причина выглядит так:
Sun Aug 20 01:09:22 2023 83.220.237.216:32783 SIGUSR1[soft,connection-reset] received, client-instance restarting
Sun Aug 20 01:09:25 2023 user16813/83.220.237.216:31930 [user16813] Inactivity timeout (--ping-restart), restarting
Sun Aug 20 01:09:25 2023 user16813/83.220.237.216:31930 SIGUSR1[soft,ping-restart] received, client-instance restarting
Sun Aug 20 01:09:32 2023 TCP connection established with [AF_INET]83.220.237.216:32784
Sun Aug 20 01:09:33 2023 83.220.237.216:32784 TLS: Initial packet from [AF_INET]83.220.237.216:32784, sid=3a6001b1 25640f6f
Но кроме этого есть и другая проблема. С вашего IP адреса каждую минуту и даже чаще происходят попытки подключения. Для примера так:
Sun Aug 20 00:37:38 2023 TCP connection established with [AF_INET]83.220.237.216:29315
Sun Aug 20 00:37:39 2023 83.220.237.216:29315 TLS: Initial packet from [AF_INET]83.220.237.216:29315, sid=a444c042 97fbe8f2
Sun Aug 20 00:37:40 2023 83.220.237.216:29315 peer info: IV_VER=2.3.11
Sun Aug 20 00:37:40 2023 83.220.237.216:29315 peer info: IV_PLAT=linux
Sun Aug 20 00:37:40 2023 83.220.237.216:29315 peer info: IV_PROTO=2
Sun Aug 20 00:37:41 2023 83.220.237.216:29315 PLUGIN_CALL: POST /usr/lib/openvpn/radiusplugin.so/PLUGIN_AUTH_USER_PASS_VERIFY status=1
Sun Aug 20 00:37:41 2023 83.220.237.216:29315 PLUGIN_CALL: plugin function PLUGIN_AUTH_USER_PASS_VERIFY failed with status 1: /usr/lib/openvpn/radiusplugin.so
Sun Aug 20 00:37:41 2023 83.220.237.216:29315 TLS Auth Error: Auth Username/Password verification failed for peer
Sun Aug 20 00:37:41 2023 83.220.237.216:29315 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 DHE-RSA-AES256-GCM-SHA384
Sun Aug 20 00:37:41 2023 83.220.237.216:29315 Peer Connection Initiated with [AF_INET]83.220.237.216:29315
Sun Aug 20 00:37:43 2023 83.220.237.216:29315 PUSH: Received control message: 'PUSH_REQUEST'
Sun Aug 20 00:37:43 2023 83.220.237.216:29315 Delayed exit in 5 seconds
Sun Aug 20 00:37:43 2023 83.220.237.216:29315 SENT CONTROL [UNDEF]: 'AUTH_FAILED' (status=1)
Sun Aug 20 00:37:44 2023 83.220.237.216:29315 Connection reset, restarting [0]
Sun Aug 20 00:37:44 2023 83.220.237.216:29315 SIGUSR1[soft,connection-reset] received, client-instance restarting
Sun Aug 20 00:37:54 2023 TCP connection established with [AF_INET]83.220.237.216:29316
Sun Aug 20 00:37:55 2023 83.220.237.216:29316 TLS: Initial packet from [AF_INET]83.220.237.216:29316, sid=1b9f7860 306f5b9e
Sun Aug 20 00:37:56 2023 83.220.237.216:29316 peer info: IV_VER=2.3.11
Sun Aug 20 00:37:56 2023 83.220.237.216:29316 peer info: IV_PLAT=linux
Sun Aug 20 00:37:56 2023 83.220.237.216:29316 peer info: IV_PROTO=2
Sun Aug 20 00:37:57 2023 83.220.237.216:29316 PLUGIN_CALL: POST /usr/lib/openvpn/radiusplugin.so/PLUGIN_AUTH_USER_PASS_VERIFY status=1
Sun Aug 20 00:37:57 2023 83.220.237.216:29316 PLUGIN_CALL: plugin function PLUGIN_AUTH_USER_PASS_VERIFY failed with status 1: /usr/lib/openvpn/radiusplugin.so
Sun Aug 20 00:37:57 2023 83.220.237.216:29316 TLS Auth Error: Auth Username/Password verification failed for peer
Sun Aug 20 00:37:57 2023 83.220.237.216:29316 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 DHE-RSA-AES256-GCM-SHA384
Sun Aug 20 00:37:57 2023 83.220.237.216:29316 Peer Connection Initiated with [AF_INET]83.220.237.216:29316
Sun Aug 20 00:37:59 2023 83.220.237.216:29316 PUSH: Received control message: 'PUSH_REQUEST'
Sun Aug 20 00:37:59 2023 83.220.237.216:29316 Delayed exit in 5 seconds
Sun Aug 20 00:37:59 2023 83.220.237.216:29316 SENT CONTROL [UNDEF]: 'AUTH_FAILED' (status=1)
Sun Aug 20 00:37:59 2023 83.220.237.216:29316 Connection reset, restarting [0]
Sun Aug 20 00:37:59 2023 83.220.237.216:29316 SIGUSR1[soft,connection-reset] received, client-instance restarting
Sun Aug 20 00:38:10 2023 TCP connection established with [AF_INET]83.220.237.216:29317
Sun Aug 20 00:38:10 2023 83.220.237.216:29317 TLS: Initial packet from [AF_INET]83.220.237.216:29317, sid=1d6f1385 6e62e829
Sun Aug 20 00:38:12 2023 83.220.237.216:29317 peer info: IV_VER=2.3.11
Sun Aug 20 00:38:12 2023 83.220.237.216:29317 peer info: IV_PLAT=linux
Sun Aug 20 00:38:12 2023 83.220.237.216:29317 peer info: IV_PROTO=2
Sun Aug 20 00:38:13 2023 83.220.237.216:29317 PLUGIN_CALL: POST /usr/lib/openvpn/radiusplugin.so/PLUGIN_AUTH_USER_PASS_VERIFY status=1
Sun Aug 20 00:38:13 2023 83.220.237.216:29317 PLUGIN_CALL: plugin function PLUGIN_AUTH_USER_PASS_VERIFY failed with status 1: /usr/lib/openvpn/radiusplugin.so
Sun Aug 20 00:38:13 2023 83.220.237.216:29317 TLS Auth Error: Auth Username/Password verification failed for peer
Sun Aug 20 00:38:13 2023 83.220.237.216:29317 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 DHE-RSA-AES256-GCM-SHA384
Sun Aug 20 00:38:13 2023 83.220.237.216:29317 Peer Connection Initiated with [AF_INET]83.220.237.216:29317
Sun Aug 20 00:38:15 2023 83.220.237.216:29317 PUSH: Received control message: 'PUSH_REQUEST'
Sun Aug 20 00:38:15 2023 83.220.237.216:29317 Delayed exit in 5 seconds
Sun Aug 20 00:38:15 2023 83.220.237.216:29317 SENT CONTROL [UNDEF]: 'AUTH_FAILED' (status=1)
Sun Aug 20 00:38:15 2023 83.220.237.216:29317 Connection reset, restarting [0]
Sun Aug 20 00:38:15 2023 83.220.237.216:29317 SIGUSR1[soft,connection-reset] received, client-instance restarting
Sun Aug 20 00:38:25 2023 TCP connection established with [AF_INET]83.220.237.216:29318
Sun Aug 20 00:38:26 2023 83.220.237.216:29318 TLS: Initial packet from [AF_INET]83.220.237.216:29318, sid=90f537f5 b6f31638
И это происходит постоянно в момент наличия уже установленного соединения. Скажите, у вас там одно устройство поднимает OpenVPN соединение или есть еще какое-то устройство в сети, которое пытается подключиться с адреса 83.220.237.216?