403 Error Technology Our indexers use cloud infrastructure and identify as indexing bots (more info). Only legitimate companies use known bots. Ethical companies require other ethical companies like ourselves contractually to only index the web in an identifiable manner, using an identifiable bot user-agent and complying with robots.txt directives.Some sites block traffic from cloud networks and indexers that identify as bots in their user-agent header. If a site does block us or is configured to block traffic with a 403 or 202 error message it is tagged with the 403 Error technology.This does not necessarily mean we were unable to index the site.