OpenVPN Security Advisory: Dec 14, 2018
Action needed: Important update for OpenVPN Access Server

I am getting the error “digest_error: NONE: not usable”


This can occur if you specify auth none and also tls-auth in your client profile. This occurs because tls-auth needs an auth digest, but none was specified. There's a straightforward fix: just remove the tls-auth directive, since it can't be enabled anyway unless you have a non-none auth directive.