SOCK: Non authoritative – host not found

Hi there
These days I am getting a message that says:
download failed (SOCK: Non authoritative – host not found) –……..
View image:
Is this a problem of the website in general, of gsa ser or of some configuration?
GSA SER has been working correctly these days, but I made some changes, like just selecting dofollow and suddenly those messages started to appear.
Any ideas?