CF caused production outage (domain unavailable) despite worker requests/sub-requests < 100K cause the rate limit issue

I had created a simple worker with a route on my account for a sub-domain, on the next day our whole domain went down and it wasn’t accessible until i delete the route/worker. The error message we got was
“Error 1027, The website has been temporarily rate limited”. However when i looked at the Analytics-> Workers section, i see Total requests stayed less than the 100K (< 50K). I am not clear why the rate limit was triggered despite the traffic is low. All i did was just added a worker but that didn’t seemed to process not more 200 requests in last 24 hours and total requests for all workers is less than 50K.