Dns issue when openvpn connected

Sometimes when openvpn client was connected, the clients can not open any webpage.
But ping google.com was ok.
Unless I turned off Override DNS Settings for All Clients and turned it on again and press the Apply button, the www web was OK immediately.
I have a GL-MT300N-V2(v3.105). Does anyone have this problem?

Hi langrenfengzi:
I have test GL-MT300N-V2(v3.105).The openvn is ok whether you turned off Override DNS Settings for All Clients or not.And it don’t have to ‘turned off Override DNS Settings for All Clients and turned it on again and press the Apply button’.

But there is no communication while you are setting up OpenVPN.About a few seconds,communication will resume.