When the power light blinks green that means the Access Point is not able to get a network IP address. It could be your ISP modem/router as they are generally configured to provide this automatically using a protocol called DHCP.
I would try to connect a device directly to the switch port (like a laptop) with Ethernet cable and see if it gets an IP and connected to the internet. You should also connect directly to the ISP modem to see where the problem lies.
You may also want to reboot your modem from the internet provider.