diff --git a/Dockerfile.zammad b/Dockerfile.zammad
index 6e91a71..fa5931a 100644
--- a/Dockerfile.zammad
+++ b/Dockerfile.zammad
@@ -31,7 +31,7 @@ COPY install-zammad.sh /tmp
 RUN chmod +x /tmp/install-zammad.sh;/bin/bash -l -c /tmp/install-zammad.sh
 
 # cleanup
-RUN apt-get remove --purge -y git-core build-essential bzip2 ca-certificates libffi-dev libgdbm3 libssl-dev procps zlib1g-dev && \
+RUN apt-get remove --purge -y git-core build-essential bzip2 libffi-dev libgdbm3 libssl-dev procps zlib1g-dev && \
     apt-get autoremove -y && \
     rm -rf /var/lib/apt/lists/*