When I use the WHOIS portal for search, why do I receive the “WHOIS LIMIT EXCEEDED” error message?

When I use the WHOIS portal for search, why do I receive the “WHOIS LIMIT EXCEEDED” error message?

Public Interest Registry has introduced rate-limiting logic on the WHOIS Port 43 server and similar rate-limiting logic on the Public Interest Registry website.

Public Interest Registry monitors all IP addresses accessing the WHOIS Port 43 server. All traffic is logged, and rate-limit validation logic is applied to limit access by any given IP address. If a unique IP address exceeds the limit, the query will be stopped, and the error message will be displayed.

Public Interest Registry accredited registrars who submit queries through the web-based WHOIS search mechanism are limited to 30 queries per minute.