@ananthbh 

Usually the problem is that the data packets from the VPN client aren't being forwarded to the router where the VPN server is running on.

The first thing to check is if the IP address of the A6's "Internet" connection is a public or a private IPv4 address. You can see that "Internet" IP address right after you log in to the web GUI via a browser and scroll down a bit.

If that IP address falls within any of the following IP address ranges, then your A6 is not being assigned a public IP address, which means you can't just easily reach it via the Internet.
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
100.64.0.0 - 100.127.255.255

How is you Internet connection set up? Is your A6 connected to some sort of modem that was provided by the ISP? Do you have access to that device (physical access and login credentials)? 

@woozle 

Hi, thanks for your reply. Yes, my IP address falls within this range 10.0.0.0 - 10.255.255.255. 

There is no modem from my ISP at least in my house. There is a cable/fiber line that comes from somewhere that is connected to my modem

@ananthbh 

That cable/fiber modem you mention, can you provide the make and model number of it?

Is it a simple pure modem, like a box with one socket for the fiber cable and another single socket for the Ethernet cable?

Does the modem have some sort of configuration GUI similar to the one of the router?