OpenVPN client stopped working - TLS handshake failed

dd2023

I'm not sure what is going on. Can someone help?

I've been using OpenVPN client on Windows 10 for a while now. (I'm currently traveling abroad.) But today it stopped working. To the best of my knowledge I did not change anything neither in my laptop here, nor on the server side.

Here's what the OpenVPN client giving me in the log when I try to connect:

Sat Sep 2 05:43:48 2023 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.
Sat Sep 2 05:43:48 2023 DEPRECATED OPTION: --cipher set to 'AES-256-CBC' but missing in --data-ciphers (AES-256-GCM:AES-128-GCM). OpenVPN ignores --cipher for cipher negotiations.
Sat Sep 2 05:43:48 2023 OpenVPN 2.6.6 [git:v2.6.6/c9540130121bfc21] Windows-MSVC [SSL (OpenSSL)] [LZO] [LZ4] [PKCS11] [AEAD] [DCO] built on Aug 15 2023
Sat Sep 2 05:43:48 2023 Windows version 10.0 (Windows 10 or greater), amd64 executable
Sat Sep 2 05:43:48 2023 library versions: OpenSSL 3.1.2 1 Aug 2023, LZO 2.10
Sat Sep 2 05:43:48 2023 DCO version: v0
Sat Sep 2 05:43:51 2023 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Sat Sep 2 05:43:51 2023 TCP/UDP: Preserving recently used remote address: [AF_INET]<my_ip>:1194
Sat Sep 2 05:43:51 2023 UDPv4 link local: (not bound)
Sat Sep 2 05:43:51 2023 UDPv4 link remote: [AF_INET]<my_ip>:1194
Sat Sep 2 05:44:51 2023 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Sat Sep 2 05:44:51 2023 TLS Error: TLS handshake failed
Sat Sep 2 05:44:51 2023 SIGUSR1[soft,tls-error] received, process restarting
Sat Sep 2 05:44:52 2023 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Sat Sep 2 05:44:52 2023 TCP/UDP: Preserving recently used remote address: [AF_INET]<my_ip>:1194
Sat Sep 2 05:44:52 2023 UDPv4 link local: (not bound)
Sat Sep 2 05:44:52 2023 UDPv4 link remote: [AF_INET]<my_ip>:1194
Sat Sep 2 05:45:53 2023 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Sat Sep 2 05:45:53 2023 TLS Error: TLS handshake failed
Sat Sep 2 05:45:53 2023 SIGUSR1[soft,tls-error] received, process restarting
Sat Sep 2 05:45:54 2023 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Sat Sep 2 05:45:54 2023 TCP/UDP: Preserving recently used remote address: [AF_INET]<my_ip>:1194
Sat Sep 2 05:45:54 2023 UDPv4 link local: (not bound)
Sat Sep 2 05:45:54 2023 UDPv4 link remote: [AF_INET]<my_ip>:1194

On the server-side, I'm using my Synology NAS in my apartment in the US with the following setup:

https://i.imgur.com/JObZbtz.png