There are a few things to consider when a follow or Unfollow request fails.
Connectivity issues between your browser to our hosting providers and/or our servers.
Temporary connectivity issues related to Twitter API servers (which happens time-to-time).
You may be reached to your account's rate limits based on your usage patterns which are determined by Twitter algorithms.
When a request fails, we don't remove it from your search results. You can always send the same request again on Circleboom after refreshing your Circleboom browser tab.