Liverpool will not be able to travel to Germany for the first leg of their Champions League last-16 tie against RB Leipzig on 16 February.
Germany has banned most travellers from countries, including the UK, hit hard by new variants of Covid-19.
A German interior ministry statement said Bundesliga club Leipzig had been told the fixture “does not meet the requirements for an exception”.
Uefa said it was “in touch with the respective clubs” about the tie.
Liverpool are being kept informed of developments as discussions take place about a solution.
European football’s governing body Uefa has updated its regulations for the knockout stages of the Champions League and Europa League amid the ongoing coronavirus pandemic.
If restrictions imposed in a country could result in a match not taking place, “the home club must propose a suitable alternative venue, which may be in a neutral country”.
However, if the host club fails to do that and it is not possible to play the game at another venue or on a different date, Uefa says it will deem the match to have been forfeited, with the home side losing 3-0.
With Germany’s restrictions in place until 17 February, an option could be to reverse the tie so Liverpool host the first leg. The second leg is scheduled to take place on 10 March.
Uefa added: “In all cases, the venue of a match must be approved by the Uefa administration, which has the right to assign an alternative venue for any particular match or even to decide that either or both legs of the relevant round to be rescheduled and/or played in a neutral country (within the territory of a Uefa member association) and/or organised as a single-leg.
“These decisions are final.”