sudo openvpn ./vpnbook-us2-udp25000.ovpn
[sudo] пароль для alex:        
Попробуйте ещё раз.
[sudo] пароль для alex:       
2023-01-14 16:41:44 WARNING: Compression for receiving enabled. Compression has been used in the past to break encryption. Sent packets are not compressed unless "allow-compression yes" is also set.
2023-01-14 16:41:44 DEPRECATED OPTION: --cipher set to 'AES-128-CBC' but missing in --data-ciphers (AES-256-GCM:AES-128-GCM). Future OpenVPN version will ignore --cipher for cipher negotiations. Add 'AES-128-CBC' to --data-ciphers or change --cipher 'AES-128-CBC' to --data-ciphers-fallback 'AES-128-CBC' to silence this warning.
2023-01-14 16:41:44 OpenVPN 2.5.5 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] built on Jul 14 2022
2023-01-14 16:41:44 library versions: OpenSSL 3.0.2 15 Mar 2022, LZO 2.10
Enter Auth Username: vpnbook
🔐 Enter Auth Password: *******                 
2023-01-14 16:42:01 WARNING: No server certificate verification method has been enabled.  See http://openvpn.net/howto.html#mitm for more info.
2023-01-14 16:42:01 OpenSSL: error:0A00018E:SSL routines::ca md too weak
2023-01-14 16:42:01 Cannot load inline certificate file
2023-01-14 16:42:01 Exiting due to fatal error

 

data-ciphers AES-256-GCM:AES-128-GCM:BF-CBC

data-ciphers-fallback BF-CBC

tls-cipher DEFAULT:@SECLEVEL=0

Последняя строчка решает и да конфиг клиента ovpn