diff --git a/crab/ib-run-pr-crab.sh b/crab/ib-run-pr-crab.sh
index 20187fc8186..c5b99b86894 100755
--- a/crab/ib-run-pr-crab.sh
+++ b/crab/ib-run-pr-crab.sh
@@ -60,7 +60,7 @@ do
     while [ "${GRIDSITE}" = "" ]
     do
       sleep 10
-      export GRIDSITE=$(curl -s -X GET --cert "/tmp/x509up_u${ID}" --key "/tmp/x509up_u${ID}" --capath "/etc/grid-security/certificates/" "https://cmsweb.cern.ch:8443/crabserver/prod/task?subresource=search&workflow=${TASK_ID}" | grep -o "http.*/${TASK_ID}")
+      export GRIDSITE=$(curl -s -X GET --cert "${X509_USER_PROXY}" --key "${X509_USER_PROXY}" --capath "/etc/grid-security/certificates/" "https://cmsweb.cern.ch:8443/crabserver/prod/task?subresource=search&workflow=${TASK_ID}" | grep -o "http.*/${TASK_ID}")
     done
 
     # Store information for the monitoring job