diff --git a/jitsi_admin_application_dockerfile.txt b/jitsi_admin_application_dockerfile.txt
index ecd9e96..d698ef3 100644
--- a/jitsi_admin_application_dockerfile.txt
+++ b/jitsi_admin_application_dockerfile.txt
@@ -31,7 +31,7 @@ RUN apk --no-cache add \
     php83-sockets \
     && rm -rf /var/cache/apk/*
 
-RUN sed -i 's/^;date.timezone =.*$/date.timezone = "Europe/Berlin"/' /etc/php83/php.ini
+RUN sed -i 's/^;date.timezone =.*$/date.timezone = "Europe\/Berlin"/' /etc/php83/php.ini
 
 RUN mkdir /etc/service/crond \
     && echo "#!/bin/sh -e" > /etc/service/crond/run \