diff --git a/pkg/services/sqlstore/migrations/ualert/channel.go b/pkg/services/sqlstore/migrations/ualert/channel.go
index 333fc3ff2df..d55d4e63e2c 100644
--- a/pkg/services/sqlstore/migrations/ualert/channel.go
+++ b/pkg/services/sqlstore/migrations/ualert/channel.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net/url"
 	"sort"
 	"strings"
 
@@ -127,6 +128,22 @@ func (m *migration) makeReceiverAndRoute(ruleUid string, orgID int64, channelUid
 		if err != nil {
 			return err
 		}
+
+		// Grafana accepts any type of string as a URL for the Slack notification channel.
+		// However, the Alertmanager will fail if provided with an invalid URL we have two options at this point:
+		// Either we fail the migration or remove the URL, we've chosen the latter and assume that the notification
+		// channel was broken to begin with.
+		if c.Type == "slack" {
+			u, ok := decryptedSecureSettings["url"]
+			if ok {
+				_, err := url.Parse(u)
+				if err != nil {
+					m.mg.Logger.Warn("slack notification channel had invalid URL, removing", "name", c.Name, "uid", c.Uid, "org", c.OrgID)
+					delete(decryptedSecureSettings, "url")
+				}
+			}
+		}
+
 		portedChannels = append(portedChannels, &PostableGrafanaReceiver{
 			UID:                   uid,
 			Name:                  c.Name,
diff --git a/pkg/services/sqlstore/migrations/ualert/channel_test.go b/pkg/services/sqlstore/migrations/ualert/channel_test.go
new file mode 100644
index 00000000000..26ea14e6a95
--- /dev/null
+++ b/pkg/services/sqlstore/migrations/ualert/channel_test.go
@@ -0,0 +1,119 @@
+package ualert
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/grafana/pkg/components/simplejson"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
+	"github.com/grafana/grafana/pkg/util"
+)
+
+func Test_makeReceiverAndRoute(t *testing.T) {
+	emptyMigration := func() *migration {
+		return &migration{
+			mg: &migrator.Migrator{
+				Logger: log.New("test"),
+			},
+			migratedChannelsPerOrg:    make(map[int64]map[*notificationChannel]struct{}),
+			portedChannelGroupsPerOrg: make(map[int64]map[string]string),
+			seenChannelUIDs:           make(map[string]struct{}),
+		}
+	}
+
+	generateChannel := func(channelType string, settings map[string]interface{}, secureSettings map[string]string) *notificationChannel {
+		uid := util.GenerateShortUID()
+		return &notificationChannel{
+			ID:                    rand.Int63(),
+			OrgID:                 rand.Int63(),
+			Uid:                   uid,
+			Name:                  fmt.Sprintf("Test-%s", uid),
+			Type:                  channelType,
+			DisableResolveMessage: rand.Int63()%2 == 0,
+			IsDefault:             rand.Int63()%2 == 0,
+			Settings:              simplejson.NewFromAny(settings),
+			SecureSettings:        GetEncryptedJsonData(secureSettings),
+		}
+	}
+
+	t.Run("Slack channel is migrated", func(t *testing.T) {
+		t.Run("url is removed if it is invalid (secure settings)", func(t *testing.T) {
+			secureSettings := map[string]string{
+				"url":   invalidUri,
+				"token": util.GenerateShortUID(),
+			}
+			settings := map[string]interface{}{
+				"test": "data",
+				"some_map": map[string]interface{}{
+					"test": rand.Int63(),
+				},
+			}
+
+			channel := generateChannel("slack", settings, secureSettings)
+			channelsUid := []interface{}{
+				channel.Uid,
+			}
+			defaultChannels := make([]*notificationChannel, 0)
+			allChannels := map[interface{}]*notificationChannel{
+				channel.Uid: channel,
+			}
+
+			apiReceiver, _, err := emptyMigration().makeReceiverAndRoute(util.GenerateShortUID(), channel.OrgID, channelsUid, defaultChannels, allChannels)
+			require.NoError(t, err)
+
+			require.Len(t, apiReceiver.GrafanaManagedReceivers, 1)
+
+			receiver := apiReceiver.GrafanaManagedReceivers[0]
+
+			require.NotContains(t, receiver.SecureSettings, "url")
+			require.Contains(t, receiver.SecureSettings, "token")
+			require.Equal(t, secureSettings["token"], receiver.SecureSettings["token"])
+			actualSettings, err := receiver.Settings.Map()
+			require.NoError(t, err)
+			require.Equal(t, settings, actualSettings)
+		})
+
+		t.Run("url is removed if it is invalid (settings)", func(t *testing.T) {
+			secureSettings := map[string]string{
+				"token": util.GenerateShortUID(),
+			}
+			settings := map[string]interface{}{
+				"url":  invalidUri,
+				"test": "data",
+				"some_map": map[string]interface{}{
+					"test": rand.Int63(),
+				},
+			}
+
+			channel := generateChannel("slack", settings, secureSettings)
+			channelsUid := []interface{}{
+				channel.Uid,
+			}
+			defaultChannels := make([]*notificationChannel, 0)
+			allChannels := map[interface{}]*notificationChannel{
+				channel.Uid: channel,
+			}
+
+			apiReceiver, _, err := emptyMigration().makeReceiverAndRoute(util.GenerateShortUID(), channel.OrgID, channelsUid, defaultChannels, allChannels)
+			require.NoError(t, err)
+
+			require.Len(t, apiReceiver.GrafanaManagedReceivers, 1)
+
+			receiver := apiReceiver.GrafanaManagedReceivers[0]
+
+			require.NotContains(t, receiver.SecureSettings, "url")
+			require.Contains(t, receiver.SecureSettings, "token")
+			require.Equal(t, secureSettings["token"], receiver.SecureSettings["token"])
+			actualSettings, err := receiver.Settings.Map()
+			require.NoError(t, err)
+			delete(settings, "url")
+			require.Equal(t, settings, actualSettings)
+		})
+	})
+}
+
+const invalidUri = "�6�M��)uk譹1(�h`$�o�N>mĕ����cS2�dh![ę�	���`csB�!��OSxP�{�"