I have made a facebook app Sometimes it's working fine but sometime it's giving a cur
 

I have made a facebook app Sometimes it's working fine but sometime it's giving a curl error CurlException: 7: Failed to connect to 2a03:2880:10:1f02:face:b00c:0:2: Network is unreachable

curl error 7 means that the TCP connect fails to that host/port. You indicated that it is working 'sometimes' - but somewhere along the way you are losing packets. This could be caused by a congested router, network cabling issues, even improper duplex settings on your network card. If you can ping the next hop along the network path towards the destination and leave it running continuously you can see if the problem is in your local configuration or somewhere further down the network...