Need help. Blocked by Google while SERP scraping.

Hello everyone!

I have a question concerning Google SERP-scraping.

I have multiple class-D networks. During the last 3 months from now, I was able to get the SERPs without being bocked by Google a single time, as the scraping was very slow.
A few days ago, all class-D networks were blocked simultaneously within some minutes and I got a site instead, where you have to enter a captcha. Even after waiting and doing nothing for 24 hours, I now can only fetch one single page per IP without being blocked. When I try to scrape the second site, I am asked to enter a captcha again.

1. Do you have any clue why this happened or suggestions how to solve this problem?

2. What is your waiting-time per IP between fetching two Google pages in order to not get blocked?

3. Do you think it helps to use https to connect to Google?

Thank you very much in advance!

I'm not sure about the time, as I always use public proxies for scraping and semi dedi proxies for posting purpose.
Benefit of using the public proxies for scraping is you can change them anytime after getting blocked by Google.
Use some proxy scraping and testing that are available free on the web.

Just use proxies.

What are you using to scrape? I am not sure I understand you well but have you tried using semi dedicated or dedicated private proxies?