If you try to log on Google service or check out Gmail account through the email client, when the connection with the DotVPN is established, Google will track your query and see that it is sent from the VPN-server (which is true). Since the VPN-server address is not the same as your usual IP-address, Google security system will block the query, considering it for unauthorized access.

To solve this problem and improve the safety of work, we recommend you to use the 2-Step Verification: http://support.google.com/accounts/bin/answer.py?hl=en&answer=180744.