diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 52f18b2129475a25b258922c5a937237700733b5..eaadf70d1bb14c9ff4b26a92fec6e1b475177082 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -31,7 +31,7 @@ variables:
   # this is the image where the cpplib is installed and where the testsuite runs
   CPPINTTEST_REGISTRY_IMAGE: $CI_REGISTRY/caosdb/src/caosdb-cppinttest/testenv:$CI_COMMIT_REF_NAME
   # this is the name of the image in the /image-cache/ directory
-  CPPINTTEST_IMAGE_CACHE: caosdb/src/caosdb-cppinttest/testenv:CI_COMMIT_REF_NAME.tar
+  CPPINTTEST_IMAGE_CACHE: caosdb/src/caosdb-cppinttest/testenv:$CI_COMMIT_REF_NAME.tar