First of all, you need to make sure the MAG device is connected to the Internet and the correct MAC address is registered in the servers of the IPTV provider.
If the problem still exists, it would be caused by of the following:
Your IP address might be blocked by your IPTV provider.
To tackle this issue, you need to contact your IPTV provider for unblocking it.
If none of the mentioned methods solve your problem, you may remove the portal address from your device, reset your device, and try setting it up again as instructions.
Try restart box and router and try again.