Some of the third-party website/APIs will temporarily ban your IP from inputting too many hashes in a day. STH should display this when it finds an error from a third-party website/API related to this.
An example is https://www.cmd5.org/, when it temporarily bans you it will output Please log in ! whenever you try to search any hash. STH should catch that error and say to the user that they were temporarily banned from that certain website.