malware – Sending meaningless Addresses requests to a series of malicious IPs

i was testing somethings on browsers and i faced a case that when i browse meaningless addresses like abc/ signortest/ word/
the request sent to ip addresses hosted on linode! that some of them was reported malicious.
and i receive two different answers.(pictures attached)

  1. 4001
  2. 503 Service Unavailable

how i can understand what’s going on?

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