diff --git a/server/channels/app/post_metadata.go b/server/channels/app/post_metadata.go
index ad4b0e1336..fc87374fe3 100644
--- a/server/channels/app/post_metadata.go
+++ b/server/channels/app/post_metadata.go
@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/dyatlov/go-opengraph/opengraph"
+	"golang.org/x/net/idna"
 
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/server/channels/app/platform"
@@ -443,9 +444,23 @@ func (a *App) getCustomEmojisForPost(c request.CTX, post *model.Post, reactions
 }
 
 func (a *App) isLinkAllowedForPreview(link string) bool {
-	domains := a.normalizeDomains(*a.Config().ServiceSettings.RestrictLinkPreviews)
+	domains := normalizeDomains(*a.Config().ServiceSettings.RestrictLinkPreviews)
 	for _, d := range domains {
-		if strings.Contains(link, d) {
+		parsed, err := url.Parse(link)
+		if err != nil {
+			a.Log().Warn("Unable to parse the link", mlog.String("link", link), mlog.Err(err))
+			// We disable link preview if link is badly formed
+			// to remain on the safe side
+			return false
+		}
+		// Conforming to IDNA2008 using the UTS-46 standard.
+		cleaned, err := idna.Lookup.ToASCII(parsed.Hostname())
+		if err != nil {
+			a.Log().Warn("Unable to lookup hostname to ASCII", mlog.String("hostname", parsed.Hostname()), mlog.Err(err))
+			// Same applies if compatibility processing fails.
+			return false
+		}
+		if strings.Contains(cleaned, d) {
 			return false
 		}
 	}
@@ -453,6 +468,20 @@ func (a *App) isLinkAllowedForPreview(link string) bool {
 	return true
 }
 
+func normalizeDomains(domains string) []string {
+	// commas and @ signs are optional
+	// can be in the form of "@corp.mattermost.com, mattermost.com mattermost.org" -> corp.mattermost.com mattermost.com mattermost.org
+	return strings.Fields(
+		strings.TrimSpace(
+			strings.ToLower(
+				strings.ReplaceAll(
+					strings.ReplaceAll(domains, "@", " "),
+					",", " "),
+			),
+		),
+	)
+}
+
 // Given a string, returns the first autolinked URL in the string as well as an array of all Markdown
 // images of the form ![alt text](image url). Note that this does not return Markdown links of the
 // form [text](url).
diff --git a/server/channels/app/post_metadata_test.go b/server/channels/app/post_metadata_test.go
index 3c62f097b1..9171b9c657 100644
--- a/server/channels/app/post_metadata_test.go
+++ b/server/channels/app/post_metadata_test.go
@@ -1664,6 +1664,21 @@ func TestGetFirstLinkAndImages(t *testing.T) {
 			ExpectedFirstLink: "",
 			ExpectedImages:    []string{},
 		},
+		"test with denied domain as username, password": {
+			Input:             "link as http://example.com:example.com@example1.com/link1",
+			ExpectedFirstLink: "http://example.com:example.com@example1.com/link1",
+			ExpectedImages:    []string{},
+		},
+		"test with URL encoded": {
+			Input:             "link as https://example%E3%80%82com/link1",
+			ExpectedFirstLink: "",
+			ExpectedImages:    []string{},
+		},
+		"test with unicode": {
+			Input:             "link as https://example。com/link1",
+			ExpectedFirstLink: "",
+			ExpectedImages:    []string{},
+		},
 	} {
 		th.App.UpdateConfig(func(cfg *model.Config) {
 			*cfg.ServiceSettings.RestrictLinkPreviews = "example.com, test.com"
diff --git a/server/channels/app/team.go b/server/channels/app/team.go
index cd33057b52..4a08fcd9ab 100644
--- a/server/channels/app/team.go
+++ b/server/channels/app/team.go
@@ -356,12 +356,6 @@ func (a *App) CreateTeamWithUser(c *request.Context, team *model.Team, userID st
 	return rteam, nil
 }
 
-func (a *App) normalizeDomains(domains string) []string {
-	// commas and @ signs are optional
-	// can be in the form of "@corp.mattermost.com, mattermost.com mattermost.org" -> corp.mattermost.com mattermost.com mattermost.org
-	return strings.Fields(strings.TrimSpace(strings.ToLower(strings.Replace(strings.Replace(domains, "@", " ", -1), ",", " ", -1))))
-}
-
 func (a *App) UpdateTeam(team *model.Team) (*model.Team, *model.AppError) {
 	oldTeam, err := a.ch.srv.teamService.UpdateTeam(team, teams.UpdateOptions{Sanitized: true})
 	if err != nil {