IP range can't access multiple websites

That error is not a Cloudflare error, so these sites won’t have blocked you. That’s a network issue and my guess would be you are resolving that to a 188 address, which is known for network issues

It’s not quite clear if that is a routing issue on your ISP’s side or a Cloudflare related issue, but the official position is what was posted in that article.

Maybe try to contact your ISP and clarify if they have any routing issues.