Several things could be responsible for this. It could be your default privacy settings, your app could be “Sandboxed”, your posts could have low priority, etc..
First of all check if your app is not “sandboxed”:
Facebook->Developers->Apps->Your App Settings->Click “Status & Review” on the left. Change “Do you want to make this app and all its live features available to the general public?” switch from “No” to “Yes”.
Then check “Permissions”. “Default Activity Privacy” may be set to “Only Me”, must be “Public”
Then check “Advanced”. Some different settings here also could filter out your posts.
If none of that helps you can try to create a new Facebook app with all default settings and use it.
If you are seeing the post and it’s public, but still getting 0 views, most probably you are making an “Attached” post, but expecting the results as from “Shared” post. “Attached” posts are not included in the statistics. Please see the difference between Facebook post types.