Problem:
Your OpenVPN clients can’t connect to your OpenVPN server and the server log shows an error message like
TLS Error: cannot locate HMAC in incoming packet from [AF_INET6]::ffff:187.100.14.13:41874 (via ::ffff:25.16.25.29%xn0)
Solution:
You have enabled a TLS key (tls-auth option) in your OpenVPN configuration, but your client does not know that it should use the additional layer of authentication.
The server is looking for the HMAC in the incoming packets but can’t find it.
Either disable the tls-auth option in your server config. The config line will look like
tls-auth /var/etc/openvpn/server2.tls-auth 0
or
Enable the correct tls-auth configuration in your client. Remember that you also need to share the correct key.