About 1,500 Everton supporters face being turned away from Thursday's Uefa Cup game in Nuremberg because of fears over crowd trouble.
Everton fans with the wrong tickets will be denied entry
Uefa classified the match as high-risk after it emerged that the German club had sold a number of tickets in their home section direct to Everton fans.
"We would never recommend that supporters get tickets through the host club," said Everton spokesman Ian Ross.
"Those who bought them are being told now they can't use them."
European football's governing body has advised that the tickets be withdrawn because of fears over the potential for hooliganism.
Everton were allocated fewer than 3,000 tickets for the Franken-Stadion ground, which holds 47,000.
A large police presence is expected in the southern German city, and Nuremberg were forced to cancel the tickets to ensure Everton's fans are segregated in the stadium.
Everton said they received requests for five times the number of tickets they were allocated.
"However, we will never endorse our supporters buying tickets from the opposing team," said Ross.
"There are regulations in place for a reason and tickets bought from Nuremberg will not be valid on Thursday."
Merseyside Police have urged fans without a ticket to avoid turning up to the ground and watch the match at local venues in Nuremberg instead.