diff --git a/clientapi/producers/syncapi.go b/clientapi/producers/syncapi.go
index 5933ce1a8..2dc0c4843 100644
--- a/clientapi/producers/syncapi.go
+++ b/clientapi/producers/syncapi.go
@@ -21,12 +21,13 @@ import (
 	"strconv"
 	"time"
 
-	"github.com/matrix-org/dendrite/setup/jetstream"
-	"github.com/matrix-org/dendrite/syncapi/types"
-	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
 	log "github.com/sirupsen/logrus"
+
+	"github.com/matrix-org/dendrite/setup/jetstream"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	userapi "github.com/matrix-org/dendrite/userapi/api"
 )
 
 // SyncAPIProducer produces events for the sync API server to consume
@@ -61,7 +62,7 @@ func (p *SyncAPIProducer) SendReceipt(
 
 func (p *SyncAPIProducer) SendToDevice(
 	ctx context.Context, sender, userID, deviceID, eventType string,
-	message interface{},
+	message json.RawMessage,
 ) error {
 	devices := []string{}
 	_, domain, err := gomatrixserverlib.SplitID('@', userID)
@@ -89,24 +90,19 @@ func (p *SyncAPIProducer) SendToDevice(
 		devices = append(devices, deviceID)
 	}
 
-	js, err := json.Marshal(message)
-	if err != nil {
-		return err
-	}
-
 	log.WithFields(log.Fields{
 		"user_id":     userID,
 		"num_devices": len(devices),
 		"type":        eventType,
 	}).Tracef("Producing to topic '%s'", p.TopicSendToDeviceEvent)
-	for _, device := range devices {
+	for i, device := range devices {
 		ote := &types.OutputSendToDeviceEvent{
 			UserID:   userID,
 			DeviceID: device,
 			SendToDeviceEvent: gomatrixserverlib.SendToDeviceEvent{
 				Sender:  sender,
 				Type:    eventType,
-				Content: js,
+				Content: message,
 			},
 		}
 
@@ -115,15 +111,17 @@ func (p *SyncAPIProducer) SendToDevice(
 			log.WithError(err).Error("sendToDevice failed json.Marshal")
 			return err
 		}
-		m := &nats.Msg{
-			Subject: p.TopicSendToDeviceEvent,
-			Data:    eventJSON,
-			Header:  nats.Header{},
-		}
+		m := nats.NewMsg(p.TopicSendToDeviceEvent)
+		m.Data = eventJSON
 		m.Header.Set("sender", sender)
 		m.Header.Set(jetstream.UserID, userID)
+
 		if _, err = p.JetStream.PublishMsg(m, nats.Context(ctx)); err != nil {
-			log.WithError(err).Error("sendToDevice failed t.Producer.SendMessage")
+			if i < len(devices)-1 {
+				log.WithError(err).Warn("sendToDevice failed to PublishMsg, trying further devices")
+				continue
+			}
+			log.WithError(err).Error("sendToDevice failed to PublishMsg for all devices")
 			return err
 		}
 	}
diff --git a/federationapi/producers/syncapi.go b/federationapi/producers/syncapi.go
index 86c8c10a3..4abd3fbe5 100644
--- a/federationapi/producers/syncapi.go
+++ b/federationapi/producers/syncapi.go
@@ -64,7 +64,7 @@ func (p *SyncAPIProducer) SendReceipt(
 
 func (p *SyncAPIProducer) SendToDevice(
 	ctx context.Context, sender, userID, deviceID, eventType string,
-	message interface{},
+	message json.RawMessage,
 ) error {
 	devices := []string{}
 	_, domain, err := gomatrixserverlib.SplitID('@', userID)
@@ -92,24 +92,19 @@ func (p *SyncAPIProducer) SendToDevice(
 		devices = append(devices, deviceID)
 	}
 
-	js, err := json.Marshal(message)
-	if err != nil {
-		return err
-	}
-
 	log.WithFields(log.Fields{
 		"user_id":     userID,
 		"num_devices": len(devices),
 		"type":        eventType,
 	}).Tracef("Producing to topic '%s'", p.TopicSendToDeviceEvent)
-	for _, device := range devices {
+	for i, device := range devices {
 		ote := &types.OutputSendToDeviceEvent{
 			UserID:   userID,
 			DeviceID: device,
 			SendToDeviceEvent: gomatrixserverlib.SendToDeviceEvent{
 				Sender:  sender,
 				Type:    eventType,
-				Content: js,
+				Content: message,
 			},
 		}
 
@@ -118,16 +113,17 @@ func (p *SyncAPIProducer) SendToDevice(
 			log.WithError(err).Error("sendToDevice failed json.Marshal")
 			return err
 		}
-		m := &nats.Msg{
-			Subject: p.TopicSendToDeviceEvent,
-			Data:    eventJSON,
-			Header:  nats.Header{},
-		}
+		m := nats.NewMsg(p.TopicSendToDeviceEvent)
+		m.Data = eventJSON
 		m.Header.Set("sender", sender)
 		m.Header.Set(jetstream.UserID, userID)
 
 		if _, err = p.JetStream.PublishMsg(m, nats.Context(ctx)); err != nil {
-			log.WithError(err).Error("sendToDevice failed t.Producer.SendMessage")
+			if i < len(devices)-1 {
+				log.WithError(err).Warn("sendToDevice failed to PublishMsg, trying further devices")
+				continue
+			}
+			log.WithError(err).Error("sendToDevice failed to PublishMsg for all devices")
 			return err
 		}
 	}
diff --git a/syncapi/consumers/sendtodevice.go b/syncapi/consumers/sendtodevice.go
index 89b01d7e5..7d6aae597 100644
--- a/syncapi/consumers/sendtodevice.go
+++ b/syncapi/consumers/sendtodevice.go
@@ -19,16 +19,17 @@ import (
 	"encoding/json"
 
 	"github.com/getsentry/sentry-go"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	"github.com/nats-io/nats.go"
+	log "github.com/sirupsen/logrus"
+
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/jetstream"
 	"github.com/matrix-org/dendrite/setup/process"
 	"github.com/matrix-org/dendrite/syncapi/notifier"
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/types"
-	"github.com/matrix-org/gomatrixserverlib"
-	"github.com/matrix-org/util"
-	"github.com/nats-io/nats.go"
-	log "github.com/sirupsen/logrus"
 )
 
 // OutputSendToDeviceEventConsumer consumes events that originated in the EDU server.
@@ -79,16 +80,18 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(ctx context.Context, msgs []
 	_, domain, err := gomatrixserverlib.SplitID('@', userID)
 	if err != nil {
 		sentry.CaptureException(err)
+		log.WithError(err).Errorf("send-to-device: failed to split user id, dropping message")
 		return true
 	}
 	if domain != s.serverName {
+		log.Tracef("ignoring send-to-device event with destination %s", domain)
 		return true
 	}
 
 	var output types.OutputSendToDeviceEvent
 	if err = json.Unmarshal(msg.Data, &output); err != nil {
 		// If the message was invalid, log it and move on to the next message in the stream
-		log.WithError(err).Errorf("output log: message parse failure")
+		log.WithError(err).Errorf("send-to-device: message parse failure")
 		sentry.CaptureException(err)
 		return true
 	}
@@ -105,7 +108,7 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(ctx context.Context, msgs []
 	)
 	if err != nil {
 		sentry.CaptureException(err)
-		log.WithError(err).Errorf("failed to store send-to-device message")
+		log.WithError(err).Errorf("send-to-device: failed to store message")
 		return false
 	}
 
diff --git a/syncapi/syncapi_test.go b/syncapi/syncapi_test.go
index c81256aa7..a4985dbf4 100644
--- a/syncapi/syncapi_test.go
+++ b/syncapi/syncapi_test.go
@@ -624,9 +624,7 @@ func testSendToDevice(t *testing.T, dbType test.DBType) {
 		// Send to-device messages of type "m.dendrite.test" with content `{"dummy":"message $counter"}`
 		for i := 0; i < tc.sendMessagesCount; i++ {
 			msgCounter++
-			msg := map[string]string{
-				"dummy": fmt.Sprintf("message %d", msgCounter),
-			}
+			msg := json.RawMessage(fmt.Sprintf(`{"dummy":"message %d"}`, msgCounter))
 			if err := producer.SendToDevice(ctx, user.ID, user.ID, alice.ID, "m.dendrite.test", msg); err != nil {
 				t.Fatalf("unable to send to device message: %v", err)
 			}