It looks like you're new here. If you want to get involved, click one of these buttons!
I get this all the time as well, because the sites change something in their markup and then SEREngines doesn't find the text it is programmed to react to. The percentage goes up and down again, but never are all the sites accessible. What you can do to improve your scoring with SEREngines, though, is to use good emails and good proxies. Many of the sites have quite good security filters, so you'll have much more chances with a residential proxy and an email than with a mail.ru and a püblic proxy
Yes, I've always had around 10-15 engines that wouldn't work. And Yandex.com and .ru doesn't work for me for a year already. Does it work for you?