screenshot is below
Solution
That JSSDK indicates that you are using the wrong URL. I am not sure how you got there but that is a test server and Facebook does not work on the test server. Kindly do the following. - log out - sign in through the website or app.usepostly.com/login
Also, please note the following: - DO NOT edit the browser URL while using the platform. - DO NOT edit permissions while connecting your facebook account, just click Continue...