Auto-update for proxies

Ok, I have a page where, y proxies are automatically updated. How and where I can import link to this page in GSA SER?

SER options->submission->use proxies->configure->add/edit providers->add url there and uncheck all other providers.

Ok, proxies are added, but SER doesn't automatically check if they are working plus somehow they doesn't work. When I add them manually they are OK. Plus, I lost the original URL in this field (it may be the source of problem why they don't seem to work):

Can you share original URL here?

Thats not the place you should add a procied. Thats a test url. There is a button to add/edit proviers on that dialog, below the list!

Yeah, I added the proxy url here:

And then when I click on 'Find online' proxies were found but they doesn't seem to work cause (maybe) I have changed url field below 'Check if anonymous'. So my question is: what is the original (default) url to test whether proxies are anonymous or not? Cause when I add the same proxies from the file the program asks me to test them and they work fine.

the default one is http://proxyjudge.us/judge.php