diff --git a/Dockerfile b/Dockerfile
index 0ca7f11..112dd9f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,8 +7,8 @@ RUN apt update && \
     apt install -y iproute2 iputils-ping
 
 # Default nginx proxy envs
-ENV NGINX_PROXY_SOURCE_PORT=${NGINX_PROXY_SOURCE_PORT:-Please configure NGINX_PROXY_SOURCE_PORT env!}
-ENV NGINX_PROXY_SOURCE_ADDRESS=${NGINX_PROXY_SOURCE_ADDRESS:-Please configure NGINX_PROXY_SOURCE_ADDRESS env!}
+ENV NGINX_PROXY_SOURCE_PORT=${NGINX_PROXY_SOURCE_PORT:-"Please configure NGINX_PROXY_SOURCE_PORT env!"}
+ENV NGINX_PROXY_SOURCE_ADDRESS=${NGINX_PROXY_SOURCE_ADDRESS:-"Please configure NGINX_PROXY_SOURCE_ADDRESS env!"}
 
 # Copy default nginx configuration
 COPY default.nginx.conf /etc/nginx/nginx.conf