diff --git a/postfix/Makefile b/postfix/Makefile
index a46a4d6..177bc23 100644
--- a/postfix/Makefile
+++ b/postfix/Makefile
@@ -10,8 +10,8 @@ POSTFIX_VERSION=$(VERSION)
 
 build:
 	docker build --build-arg DOVECOT_VERSION=$(DOVECOT_VERSION) \
-    --build-arg POSTFIX_VERSION=$(POSTFIX_VERSION) \
-    -t $(REGISTRY)/$(IMAGE):$(VERSION)-$(BUILD) .
+		--build-arg POSTFIX_VERSION=$(POSTFIX_VERSION) \
+		-t $(REGISTRY)/$(IMAGE):$(VERSION)-$(BUILD) .
 
 push:
 	docker push $(REGISTRY)/$(IMAGE):$(VERSION)-$(BUILD)