For now i would suggest that you upgrade to the recent GVM-9 release. In this release the communication between the openvassd and openvasmd is done via file/unix sockets where you don’t need to care about SSL/TLS certificates anymore.
Thanks you for your answer.
I’m not sure how to do that, as I wrote before I’m new with OpenVAS.
I checked the kink you sent me not sure waht should I do with the new libraries, and how do I upgrade it?
I forgot to mention it before, I;m using it as a VM, so if upgrade means install from scrach no problem. If yes, is there a link that I can get for an iso/OVA file?