The club have been sanctioned following ‘crowd disturbances’ during their 2-2 draw at Genk
Die Premierliga club have also been fined a total of €34,500 (£29,260) volg die 2-2 draw in Belgium on 4 November.
According to a statement from Uefa, the ticket ban and a fine of 30,000 euros (£25,444) were imposed for “crowd disturbances”. An additional €4,500 (£3,816) fine was handed down for the “throwing of objects” by travelling fans.
West Ham are due to travel to Rapid Vienna in the Europa League on 25 November.
According to the Hammers’ official website, a full allocation of 1,700 tickets for the visit to the Allianz Stadion in the Austrian capital has already sold out.
West Ham top Europa League Group H, with the draw at Genk’s Luminus Arena earlier this month leaving them with 10 points from a possible 12.
Fan trouble also flared when Rapid Vienna were beaten 2-0 at the London Stadium aan 30 Oktober, leading to three arrests.
A statement released by West Ham on Monday evening read: “West Ham United can confirm that we have received an email late this afternoon informing us that we are subject to sanctions from Uefa in relation to our Europa League Group H fixture against KRC Genk on Thursday 4 November.
“The Club has been fined 34,500 Euros and also informed that our supporters are unable to travel for our next Europa League away fixture.
“The Club are urgently seeking clarification from Uefa, particularly given the extremely short notice of the sanction, which will impact our supporters who have already bought tickets and made arrangements to travel to Austria our match at Rapid Vienna in just over a week.
“We are surprised to receive these sanctions and disappointed for the fans who have behaved impeccably and supported the team throughout and will now be unable to travel to the next away Europa League fixture.
“The Club has requested the full written reasons from Uefa regarding these sanctions and have asked them to expedite our request given that further delay could impact supporters once again.
‘The Club fully appreciates that supporters will have booked return travel and accommodation in Austria and are stressing this in our dialogue with Uefa. We will update supporters as soon as we are able to with further information.
“Finally, we would like to assure those supporters who have already purchased one of the 1,700 tickets that sold out our allocation for this game that they will be automatically refunded by the Club should Uefa rule the sanctions stand and that they relate to next week’s match in Austria.”
David Moyes’ Hammers, who sit third in the Premier League table ahead of Saturday’s trip to Wolves, complete the group stage of the European competition at home to Croatian side Dinamo Zagreb aan 9 Desember.