This probably isn't a bug, but I am reporting it anyway. Just in case. I believe it was after the 1.5.10 patch in August that autolink stopped working for this site. When "Convert URLs to Page Titles" is checked, Links to this site get renamed "Solicitud Rechazada", which means "request rejected" http://dle.rae.es/?id=OlQ6yC8 They probably see it as a bot connecting to their servers, instead of a human (which is true). Confirmed in a XF demo account. Cheers!