ExpressVPn dns leak

Is there any solution for dns leak with router os and l2tp vpn?? My configuration is similar to this https://www.youtube.com/watch?v=0gQpxt6AyIQ vpn is working but with dns leak. There is no leak with tplink router.
I found temporary solution i need to add manualy dns but i have to click apply few Times a day i dont know why. Any help?? I found dns adress in tplink is there any Way to mikrotik gets dns like tplink??