same problem coming with me tooeven srapebox authority not replying on this issue
Had the same problem, the sulution is google passed proxies
This is just a proxy issue. Using harvested proxies has always been an issue. Even if it says google passed in Scrapebox, google's standards may be different/updated. For harvesting best thing to use is semi-dedicated which you can get for a descent price. With 100, I'm able to scrape continuously all day long with no issues what so ever.
almost certainly to do with public proxies i would say