diff --git a/ci/run-jjb.py b/ci/run-jjb.py
index e78b56b..b53a14a 100755
--- a/ci/run-jjb.py
+++ b/ci/run-jjb.py
@@ -120,7 +120,10 @@
             raise ValueError("%s" % e)
 
         data = proc.stdout.decode()
+        stderr = proc.stderr.decode()
         if proc.returncode != 0:
+            print(f"STDOUT: {data}")
+            print(f"STDERR: {stderr}")
             raise ValueError("command has failed with code '%s'" % proc.returncode)
 
         try: