diff --git a/internal/dnsproxy/proxy.go b/internal/dnsproxy/proxy.go
index f7ff9e2e..d8131918 100644
--- a/internal/dnsproxy/proxy.go
+++ b/internal/dnsproxy/proxy.go
@@ -1,7 +1,6 @@
 package dnsproxy
 
 import (
-	"fmt"
 	"net"
 	"runtime/debug"
 	"time"
@@ -80,14 +79,14 @@ func (d *DNSProxy) Lookup(m *dns.Msg) (*dns.Msg, error) {
 		target := net.JoinHostPort(upstream, "53")
 		resp, _, err := d.udpClient.Exchange(m, target)
 		if err != nil && firstErr == nil {
-			logrus.Warnf(errors.Wrap(err, fmt.Sprintf("DNS lookup failed for upstream %s", upstream)).Error())
+			logrus.Warnf("DNS lookup failed for upstream %s: %v", upstream, err)
 			firstErr = err
 		} else if err == nil {
 			// Retry truncated responses over TCP
 			if resp.Truncated {
 				resp, _, err = d.tcpClient.Exchange(m, target)
 				if err != nil && firstErr == nil {
-					logrus.Warnf(errors.Wrap(err, fmt.Sprintf("DNS lookup failed over TCP for upstream %s", upstream)).Error())
+					logrus.Warnf("DNS lookup failed over TCP for upstream %s: %v", upstream, err)
 					firstErr = err
 					continue
 				}
diff --git a/internal/dnsproxy/proxy_test.go b/internal/dnsproxy/proxy_test.go
index 40fab589..b58dc765 100644
--- a/internal/dnsproxy/proxy_test.go
+++ b/internal/dnsproxy/proxy_test.go
@@ -5,6 +5,9 @@ import (
 	"net"
 	"testing"
 	"time"
+
+	"github.com/miekg/dns"
+	"github.com/patrickmn/go-cache"
 )
 
 var ffmucUpstreams, _ = net.LookupHost("dns.ffmuc.net")
@@ -56,3 +59,39 @@ func TestDNSProxy_ServeDNS(t *testing.T) {
 		}
 	})
 }
+
+func TestDNSProxy_Lookup(t *testing.T) {
+	proxy := &DNSProxy{
+		udpClient: &dns.Client{Net: "udp"},
+		tcpClient: &dns.Client{Net: "tcp"},
+		cache:     cache.New(5*time.Minute, 10*time.Minute),
+		upstream:  ffmucUpstreams,
+	}
+
+	t.Run("Cache hit", func(t *testing.T) {
+		msg := new(dns.Msg)
+		msg.SetQuestion("example.com.", dns.TypeA)
+		proxy.cache.Set(makekey(msg), msg, cache.DefaultExpiration)
+
+		resp, err := proxy.Lookup(msg)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if resp == nil {
+			t.Fatal("expected response, got nil")
+		}
+	})
+
+	t.Run("Cache miss", func(t *testing.T) {
+		msg := new(dns.Msg)
+		msg.SetQuestion("example.com.", dns.TypeA)
+
+		resp, err := proxy.Lookup(msg)
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if resp != nil {
+			t.Fatal("expected nil response, got non-nil")
+		}
+	})
+}
diff --git a/internal/services/device_service.go b/internal/services/device_service.go
index deb6e06c..d7a8198a 100644
--- a/internal/services/device_service.go
+++ b/internal/services/device_service.go
@@ -28,7 +28,7 @@ func (d *DeviceService) AddDevice(ctx context.Context, req *proto.AddDeviceReq)
 	device, err := d.DeviceManager.AddDevice(user, req.GetName(), req.GetPublicKey(), req.GetPresharedKey())
 	if err != nil {
 		ctxlogrus.Extract(ctx).Error(err)
-		return nil, status.Errorf(codes.Internal, err.Error())
+		return nil, status.Errorf(codes.Internal, "%v", err)
 	}
 
 	return mapDevice(device), nil
@@ -68,7 +68,7 @@ func (d *DeviceService) DeleteDevice(ctx context.Context, req *proto.DeleteDevic
 
 	if err := d.DeviceManager.DeleteDevice(deviceOwner, req.GetName()); err != nil {
 		ctxlogrus.Extract(ctx).Error(err)
-		return nil, status.Errorf(codes.Internal, "failed to delete device")
+		return nil, status.Errorf(codes.Internal, "failed to delete device: %v", err)
 	}
 
 	return &emptypb.Empty{}, nil
@@ -87,7 +87,7 @@ func (d *DeviceService) ListAllDevices(ctx context.Context, req *proto.ListAllDe
 	devices, err := d.DeviceManager.ListAllDevices()
 	if err != nil {
 		ctxlogrus.Extract(ctx).Error(err)
-		return nil, status.Errorf(codes.Internal, "Failed to retrieve devices")
+		return nil, status.Errorf(codes.Internal, "failed to retrieve devices: %v", err)
 	}
 
 	return &proto.ListAllDevicesRes{