After 5-15 requests, each account stops and starts the next with this message: Error [Add Targeted Friends] 3/43/5371/0/0: FacebookException -> Received an unknown error from facebook.com. Can't make sure whether it's a warning message, so let's just stop this account for security reason. Our test team will check out this unknow error as soon as possible. I am using PVAs, private proxies and I bought a captcha service. I am using the recommended random break time (3-30 seconds). Any ideas?