diff --git a/.circleci/config.yml b/.circleci/config.yml
index caa3a9f..3bb314f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -175,7 +175,7 @@ jobs:
           name: Build application Docker image
           command: |
             docker build --cache-from=offen/server -t offen/server:$DOCKER_IMAGE_TAG -f build/server/Dockerfile .
-            docker build --build-arg --cache-from=offen/proxy siteurl=$SITEURL -t offen/proxy:$DOCKER_IMAGE_TAG -f build/proxy/Dockerfile .
+            docker build --cache-from=offen/proxy --build-arg siteurl=$SITEURL -t offen/proxy:$DOCKER_IMAGE_TAG -f build/proxy/Dockerfile .
       - run:
           name: Save Docker image layer cache
           command: |