diff --git a/Dockerfile b/Dockerfile
index eed0be2..99e324a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,12 +13,14 @@ RUN apt-get update --yes && \
 RUN export url="https://github.com/pgrok/pgrok/releases/download/v1.4.1/pgrok_1.4.1_linux_"; \
   if [ `uname -m` == "aarch64" ]; then \
        export arch='arm64' \
-    && wget --quiet ${url}${arch}.tar.gz -O pgrok_linux_${arch}.tar.gz \
+    && wget --quiet ${url}${arch}.tar.gz -O pgrok_linux_${arch}.tar.gz ; \
   else \
        export arch='amd64' \
-    && wget --quiet ${url}${arch}.tar.gz -O pgrok_linux_${arch}.tar.gz \
+    && wget --quiet ${url}${arch}.tar.gz -O pgrok_linux_${arch}.tar.gz ; \
+  fi \
   && tar -xzf pgrok_linux_${arch}.tar.gz \
   && mv task /usr/local/bin/pgrok
+  
 USER ${NB_UID}
 RUN echo "install custom extensions "
 RUN pip install --extra-index-url https://git.sandbox.iuk.hdm-stuttgart.de/api/packages/grosse/pypi/simple jupyterlab-sandbox-theme==0.1.6