diff --git a/management/backup.py b/management/backup.py
index 93744d7d..13ff4a44 100755
--- a/management/backup.py
+++ b/management/backup.py
@@ -491,7 +491,8 @@ def list_target_files(config):
 				reason = "Unknown error." \
 						"Please check running 'management/backup.py --verify'" \
 						"from mailinabox sources to debug the issue."
-			raise ValueError(f"Connection to rsync host failed: {reason}")
+			msg = f"Connection to rsync host failed: {reason}"
+			raise ValueError(msg)
 
 	elif target.scheme == "s3":
 		import boto3.s3