From d9a2f834d3d3b0a828a51c691fffa6f8af276e17 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Tue, 8 Sep 2020 10:45:02 +0100
Subject: [PATCH] Backoff for 401s

---
 federationsender/internal/api.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/federationsender/internal/api.go b/federationsender/internal/api.go
index 61663be31..2a70f7ed3 100644
--- a/federationsender/internal/api.go
+++ b/federationsender/internal/api.go
@@ -70,7 +70,10 @@ func failBlacklistableError(err error, stats *statistics.ServerStatistics) (unti
 	if !ok {
 		return stats.Failure()
 	}
-	if mxerr.Code >= 500 && mxerr.Code < 600 {
+	if mxerr.Code == 401 { // invalid signature in X-Matrix header
+		return stats.Failure()
+	}
+	if mxerr.Code >= 500 && mxerr.Code < 600 { // internal server errors
 		return stats.Failure()
 	}
 	return