OpenVPN Support Forum

I'm experiencing issues connecting my Android devices to the OpenVPN server on my Synology NAS.

This was setup & tested about 3 weeks ago. Worked fine from home (inside home network, but also across mobile network.

Now on the road my Windows 11 laptop connects without any issue; using a website like What is My IP I can see all my traffic is first traveling to the VPN server a home, then onto the public internet. Also, certain video services that are only available in my home country wrok perfectly when the VPN is connected. All this is as expected.

Our Android devices however won't connect, below (and attached) the error messages we get on the devices.

I first though this might be a certificate issue so I replaced the Let's Encrypt certificate with a Sectigo certificate, generated a new profile, read that into the devices. Unfortunately, the Android devices still cannot connect. The Windows laptop works as expected.

Any idea how to resolve this?

Error messages:
This profile doesn't include a client certificate.
Continue connecting without a certificate or select one from the Android keychain?

and

There was anerror attempting to connect ot the selected server.
Error message: OpenSSLContext:SSL:Read_cleartext:BIO_read failed, cap-2576 status--1 error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed

and

There was an error attempting to connect to the selected server.
Error message: External certificate not found.
Please select proper certificate for profile.

See also:

android doesn't like the single quotes

change

verify-x509-name 'my.nas.com' name

to

verify-x509-name my.nas.com name

same problem here and now, ended without connection with error message on Synology - in file:

/var/log/systemd tail -f pkg-VPNCenter-openvpn-server.service.log

and the line which i think is the major cause is:

openvpn[6392]: 2024-08-12 12:17:42 read UDPv6 [NO-INFO]: Connection refused (code=111)

but what to hell has the UDPv6 to do here ? all the things around IPv6 are disabled... on SYN, on Firewall, on mobile it is not possible on wifi but there is IPv4 address also...

from windows client the same ovpn file works well ! aaaagh... I got headache...