Include the destination in the error of 'Destination mismatch' (#17830)

To help debug problems such as
https://github.com/element-hq/synapse/issues/17822

2 files changed, 2 insertions, 1 deletions

diff --git a/changelog.d/17830.misc b/changelog.d/17830.misc
new file mode 100644

index 0000000000..b2cd91c0ad
--- /dev/null
+++ b/changelog.d/17830.misc
@@ -0,0 +1 @@
+Include the destination in the error of 'Destination mismatch' on federation requests.
diff --git a/synapse/federation/transport/server/_base.py b/synapse/federation/transport/server/_base.py

index 9094201da0..cba309635b 100644
--- a/synapse/federation/transport/server/_base.py
+++ b/synapse/federation/transport/server/_base.py
@@ -113,7 +113,7 @@ class Authenticator:
                 ):
                     raise AuthenticationError(
                         HTTPStatus.UNAUTHORIZED,
-                        "Destination mismatch in auth header",
+                        f"Destination mismatch in auth header, received: {destination!r}",
                         Codes.UNAUTHORIZED,
                     )
         if (