KFC apologized this week for sending a mobile app alert telling German customers to “treat yourself” on Kristallnacht.

Kristallnacht, or the night of broken glass, refers to the pogroms against Jewish people in Germany and Austria carried out by Nazis in November 1938. Some consider it the beginning of the Holocaust.

On Wednesday, the Yum Brands chain sent a notification that reportedly said “It’s memorial day for Kristallnacht! Treat yourself with more tender cheese on your crispy chicken. Now at KFCheese!”

KFC said the notification contained “an obviously unplanned, insensitive and unacceptable message.”

“We understand and respect the gravity and history of this day, and remain committed to equity, inclusion and belonging for all,” KFC said in a statement.

The fried-chicken chain said that it uses a bot linked to national observances to create notifications for its mobile app. KFC said that the chain’s internal review process wasn’t followed properly, resulting in the alert going out to customers. It added that it has suspended app communications to make sure the mistake doesn’t happen again.

Recent anti-semitic comments from rapper Ye, formerly known as Kanye West, and NBA player Kyrie Irving have added to concerns about rising hate aimed at Jewish communities.