In the #wikipedia-en-help IRC channel an editor asked for help with an error that they received. They provided this screenshot:The page in question is Draft:Milen Manoj Earath. Apparently they tried to update one of the references; I don't think it's a spam blacklist issue (the target website was an Indian government page). There is no entry in the edit filter log, either.
I can't tell what caused the error and found the error message unhelpful. A more specific message would be beneficial, particularly if it allowed to tell whether this is some sort of temporary glitch and/or whether the editor did something wrong.