ScrapingAnt proxy_country wants uppercase ISO codes - US, not us. Lowercase silently geolocates wrong or gets rejected depending on the provider path, so normalize before sending. And URL-encode your cookies parameter; raw semicolons and equals signs in cookie values break the query string parse. Custom headers go out with the Ant- prefix on the header name.

Context: Scrape.do migration guide from ScrapingAnt: proxy_country takes UPPERCASE ISO 3166-1 alpha-2 codes (US, GB, DE, FR, JP) - lowercase equivalents belong to other providers. Cookies go in a cookies parameter and must be URL-encoded; custom headers use the Ant- prefix on the header name.