400. That’s an error.

Google cannot redirect you to http://www.abebooks.it/servlet/SearchResults?tn=Viaggio+e+missione+cattolica+fra+Mens%C3%A2+Bogos+e+gli+Habab+con+un+cenno+geografico+e+storico+dell%27Abissinia+di+Giuseppe+Sapeto because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.