How to use two DNS on ocserv 0.3.0 ?

[info at itnserver.com]

Hello

how to add two dns server on sample.config
I did test a few examples
--------------------------------------
ipv4-dns = 4.2.2.2
ipv4-dns = 8.8.8.8
--------------------------------------
ipv4-dns = 4.2.2.2 8.8.8.8
--------------------------------------
ipv4-dns =  4.2.2.2 , 8.8.8.8
--------------------------------------
But false
In the first example, only the first one works ( 4.2.2.2 )
In the 2nd and 3rd example the connection fails
when i'm connected, download and upload speed is ok but some web pages 
wont be loaded or loaded so slow. what could be the problem?

Please Help Me
Thanks For All help
Alex