It couldn't land at Hahn due to fog, so diverted to Manchester.
Just out of interest, why would the AN-124 not be able to divert to somewhere closer to Hahn (within a few hundred miles) assuming that the fog was wider spread ? Manchester seems a bit far to me, especially as Doncaster and EMA are both 24hrs if I recall correctly. Perhaps the crew have fond memories of a past visit to MAN and some local hostelry ;-)