Comments will start to queue if you are commenting too quickly. If for any reason you would like to remove a comment from the queue, this can be done on the History page.
The History page will display a Queued section when a queue is formed (it will not be there if there are no comments in the queue). From here you will have full control of the queue with the actions: pause/run (this can also be done in the progress bar), delete a post and delete all posts from the queue.
To remove a single post, hover, go to the actions menu and then select delete. This will remove that comment from the queue, meaning it will NOT post on Instagram. A comment can be removed from the queue when it is running or paused. However, if you know you would like to remove a particular comment from the queue we would suggest pausing the queue, removing the comment and then run the queue.
To delete the whole comment queue, hover, go to the actions menu and then select delete all queued. This will delete all of your comments from the queue.