diff --git a/Lib/email/_policybase.py b/Lib/email/_policybase.py
index 12211158f4699b..9558691402d458 100644
--- a/Lib/email/_policybase.py
+++ b/Lib/email/_policybase.py
@@ -97,7 +97,7 @@ def validate_header(name):
         raise ValueError(f"Invalid header field name {name!r}")
     # Only allow printable ASCII characters
     if any(ord(c) < 33 or ord(c) > 126 for c in name):
-        raise ValueError(f"Header field name {name!r} contains invalid characters")
+        raise ValueError(f"Invalid header field name {name!r}")
 
 def _append_doc(doc, added_doc):
     doc = doc.rsplit('\n', 1)[0]
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
index 827b36c36bd3a6..ade9d3a2ac28f5 100644
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -740,7 +740,7 @@ def test_invalid_headers(self):
         for name, value in invalid_headers:
             with self.assertRaises(ValueError) as cm:
                Message().add_header(name, value)
-            self.assertIn("Invalid header field name", str(cm.exception))
+            self.assertIn(f"Invalid header field name {name!r}", str(cm.exception))
 
         invalid_headers = [
             ('Header\x7F', 'Non-ASCII character'),
@@ -749,7 +749,7 @@ def test_invalid_headers(self):
         for name, value in invalid_headers:
             with self.assertRaises(ValueError) as cm:
                Message().add_header(name, value)
-            self.assertIn(f"Header field name {name!r} contains invalid characters", str(cm.exception))
+            self.assertIn(f"Invalid header field name {name!r}", str(cm.exception))
 
     def test_binary_quopri_payload(self):
         for charset in ('latin-1', 'ascii'):