Hi AntonK
It might be that when you entered the RSS feed URLs, they had a space at the end of the URL. If this is the case, then the validation is actually successful, but it can happen that no posts are being pulled due to an error in the backend. Could you re-add your feeds and make sure they do not have a space at the end of the URL. We have this as a bug, and this will be fixed with the next release. Please update me if re-adding the feeds and removing any spaces has fixed the issue.