hello for all mikrotik people there ..
so after setting up an open VPN connection in mikrotik as a server, and in my windows machine as a client
it give me this message : Your Certificate has expire -(see the picture below)-
so anyone encounter this before..?

Probably you have not configured working time sync in your MikroTik router and its date/time is back in 1970.
(or it was when you created the certificate)