dlvr.it is seeing a large volume of users with this error when trying to add a Twitter account. We have determined that this error is related to a known Twitter issue. However, for our users that are currently having this problem, we recommend trying the following steps:
1) Log into your Twitter account
2) Go into your third party apps and revoke access for dlvr.it
3) Try adding the Twitter account again
Update: Twitter has reported that this issue has been resolved as of 11/24/2016. Please email email@example.com with any further questions or concerns.