GSA SER and Capmonster

I am trying to figure out the best settings for GSA SER and Capmonster for solving Recaptcha. I am using Capmonster to emulate Rucaptcha, I’ve added RuCaptcha with IP and made all the proper settings.
Now, when I test the Recaptcha (from google api) I get “Server seems down”, even though CapMonster receives the captcha and obtains the token.
On Captcha Stats in GSA SER, all threads are unsuccessful. I guess Capmonster doesn’t return the sitekey to GSA?
What can I do?