When trying to enable Twitter from the voting options for a poll for the first time users are taken to Twitter page and asked to allow access to their Twitter from ExciteM.
It is required to allow access in order to be able to run a poll with Twitter component enabled.
However, you may accidentally deny access by clicking "Cancel". You will see the following message
In that case, you will be shown the following message in Twitter every consecutive time you try to enable it
In order to resolve this issue, please log out from your ExciteM account and log in again. After you do this, you will be able to enable Twitter and allow access.