When I am downloading Facebook, for every phone it shows “secure connection is not available.” Just now I have downloaded new software to my mobile ‘Nokia 2690’.
.its not the network problem its your certificates check all the cert. And mark
You will generally get this message when your Facebook security settings have secure connections enabled but the app on the device you are using does not support secure connections. I had the same issue with my HP TouchPad until I updated the Facebook app on it.
check your mobile Phones date and time