TypeError: Invalid calling object

[mathie]

View details in Rollbar: https://rollbar.com/wossname/woss.name/items/28/

TypeError: Invalid calling object
  File "https://connect.facebook.net/signals/config/1620228138297305", line 21, in q
  File "https://connect.facebook.net/signals/config/1620228138297305", line 21, in r
  File "https://connect.facebook.net/signals/config/1620228138297305", line 21, in ea
  File "https://d37gvrvc0wt4s1.cloudfront.net/js/v1.9/rollbar.min.js", line 1, in e._wrapped