diff --git a/nginx-pwa/etc/nginx/entrypoint.d/90-envsubst-on-config-js.sh b/nginx-pwa/etc/nginx/entrypoint.d/90-envsubst-on-config-js.sh
index d54d37f..6848fad 100755
--- a/nginx-pwa/etc/nginx/entrypoint.d/90-envsubst-on-config-js.sh
+++ b/nginx-pwa/etc/nginx/entrypoint.d/90-envsubst-on-config-js.sh
@@ -5,16 +5,21 @@ set -e
 
 ME=$(basename $0)
 
-test -z "$NGINX_CONFIG_JS_PATH" && exit 0
-test ! -f "$NGINX_CONFIG_JS_PATH" && exit 1
+test -z "$NGINX_CONFIG_JS_URI" && exit 0
+
+configJsPath="$NGINX_DOCUMENT_ROOT/$NGINX_CONFIG_JS_URI"
+if test ! -f "$configJsPath"; then
+  echo "$ME: ERROR: $configJsPath does not exist"
+  exit 1
+fi
 
 definedEnvs=$(printf '${%s} ' $(env | cut -d= -f1))
-if [ ! -w "$NGINX_CONFIG_JS_PATH" ]; then
-  echo >&3 "$ME: ERROR: $NGINX_CONFIG_JS_PATH exists, but is not writable"
+if [ ! -w "$configJsPath" ]; then
+  echo "$ME: ERROR: $configJsPath exists, but is not writable"
   return 0
 fi
-echo >&3 "$ME: Running envsubst on $NGINX_CONFIG_JS_PATH"
-envsubst "$definedEnvs" <"$NGINX_CONFIG_JS_PATH" >"${NGINX_CONFIG_JS_PATH}.tmp"
-mv -f "${NGINX_CONFIG_JS_PATH}.tmp" "$NGINX_CONFIG_JS_PATH"
+echo "$ME: Running envsubst on $configJsPath"
+envsubst "$definedEnvs" <"$configJsPath" >"${configJsPath}.tmp"
+mv -f "${configJsPath}.tmp" "$configJsPath"
 
 exit 0