HTTP API Access Blocked: Understanding Retry Limitations

HTTP API issue - "Ran too many times, retry in a few minutes" - why am I being blocked if the underlying website / service doesn't have a problem with me accessing it? Note that the issue is that its not allowing me to run this cell because I ran it too many times... maybe 4-5 times in a minute (with values changed). I was manually running it, not through an automation.