Most common reasons why Facebook disconnects are:
1. Token expires after 60 days
Facebook API requires users to authenticate at least once in 60 days. You can read more at FB bug report: https://developers.facebook.com/support/bugs/4323268977772690/?join_id=f5bb027c83ccf8
2. Facebook has detected what it thinks is a suspicious login attempt
This includes logging in from a device or web browser that Facebook doesn’t recognize. To protect your account, Facebook disconnects any third-party tools, like Covet.pics. Here’s what you can do to avoid this in future:
- Avoid using alias usernames for your Facebook accounts. Use the same name on Facebook that you use in everyday life, so people know who they’re connecting with.
- Don’t share your Facebook account credentials (username and password) with anyone else. Team members managing Pages or groups should be signing in with their own credentials.
- Try turning on Facebook alerts for unrecognized logins. If you start getting alerts, you can tell Facebook which devices and browsers to trust in the future. See the Facebook help article How do I get alerts about unrecognized logins to Facebook.
3. The user who connected the account to Covet.pics is no longer an Admin of the Facebook Page or group.
To connect a Facebook Page to Covet.pics, your Facebook user must be an Admin of the Page. If your Admin role is later removed, the Page will disconnect from Covet.pics. Make sure that all your Page Admins know which user is authorizing Covet.pic’s access. That user needs to remain listed as a Page Admin Admin.
4. Your Facebook account password gets updated
If you update your Facebook password, it will disconnect third-party tools, like Covet.pics.
You can read more on https://developers.facebook.com/blog/post/2011/05/13/how-to--handle-expired-access-tokens/