OpenVPN AES-128GCM plus TLS AUTH

Hi Members,

Hopefully someone can advise

I am trying to connect to a vpn provider which uses, username + password plus AES-128GCM plus tls-auth using a tls key

Now according to mikrotik site if you are using a GCM cipher, then the auth must be null but as GCM takes care of the auth portion too. however the SHA256 is required for the TLS-AUTH portion of the negotiation

How do I get around this. VPN provider is not accepting CBC cipher so that doesnt work

Regards,