diff --git a/httputil/httputil.go b/httputil/httputil.go
index a2256551..c020e064 100644
--- a/httputil/httputil.go
+++ b/httputil/httputil.go
@@ -113,7 +113,7 @@ func get(url, auth string) (*http.Response, error) {
 
 		nextTryAt := RetryClock.Now().Add(waitFor)
 		if nextTryAt.After(deadline) {
-			return nil, fmt.Errorf("unable to complete request to %s within %v", url, MaxRequestDuration)
+			return nil, fmt.Errorf("unable to complete %d requests to %s within %v. Most recent failure: %s", attempt+1, url, MaxRequestDuration, lastFailure)
 		}
 		if attempt < MaxRetries {
 			RetryClock.Sleep(waitFor)
diff --git a/httputil/httputil_test.go b/httputil/httputil_test.go
index 254e4298..1a3f2281 100644
--- a/httputil/httputil_test.go
+++ b/httputil/httputil_test.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net/http"
 	"strconv"
+	"strings"
 	"testing"
 	"time"
 )
@@ -219,10 +220,13 @@ func TestDeadlineExceeded(t *testing.T) {
 		t.Fatal("Expected request to fail with code 500")
 	}
 
-	wanted := "could not fetch http://bar: unable to complete request to http://bar within 8s"
+	wantedPrefix := "could not fetch http://bar: unable to complete "
+	wantedSuffix := " requests to http://bar within 8s. Most recent failure: HTTP 500"
+
 	got := err.Error()
-	if wanted != got {
-		t.Fatalf("Expected error %q, but got %q", wanted, got)
+	sameError := strings.HasPrefix(got, wantedPrefix) && strings.HasSuffix(got, wantedSuffix)
+	if !sameError {
+		t.Fatalf("Expected error %q, but got %q", wantedPrefix+"???"+wantedSuffix, got)
 	}
 }