diff --git a/services/graph/pkg/service/v0/api_driveitem_permissions.go b/services/graph/pkg/service/v0/api_driveitem_permissions.go
index e19eec5aa8..7d43726744 100644
--- a/services/graph/pkg/service/v0/api_driveitem_permissions.go
+++ b/services/graph/pkg/service/v0/api_driveitem_permissions.go
@@ -182,7 +182,8 @@ func (s DriveItemPermissionsService) Invite(ctx context.Context, resourceId *sto
 		cTime = createShareResponse.GetShare().GetCtime()
 		expiration = createShareResponse.GetShare().GetExpiration()
 
-		guestIdentity, err := cs3UserIdToIdentity(ctx, s.identityCache, createShareRequest.GetGrant().GetGrantee().GetUserId())
+		// the share provider stores the guest's mail address in its canonical form
+		guestIdentity, err := cs3UserIdToIdentity(ctx, s.identityCache, createShareResponse.GetShare().GetGrantee().GetUserId())
 		if err != nil {
 			s.logger.Debug().Err(err).Msg("failed to convert guest user id to identity")
 			return libregraph.Permission{}, err
diff --git a/services/graph/pkg/service/v0/api_driveitem_permissions_test.go b/services/graph/pkg/service/v0/api_driveitem_permissions_test.go
index 5c386b69f6..cf6ecd44c7 100644
--- a/services/graph/pkg/service/v0/api_driveitem_permissions_test.go
+++ b/services/graph/pkg/service/v0/api_driveitem_permissions_test.go
@@ -176,7 +176,8 @@ var _ = Describe("DriveItemPermissionsService", func() {
 				{Email: libregraph.PtrString("guest@example.com")},
 			}
 			createShareResponse.Share = &collaboration.Share{
-				Id: &collaboration.ShareId{OpaqueId: "guest123"},
+				Id:      &collaboration.ShareId{OpaqueId: "guest123"},
+				Grantee: guestGrantee("guest@example.com"),
 			}
 
 			permission, err := driveItemPermissionsService.Invite(ctx, driveItemId, driveItemInvite)
@@ -187,6 +188,23 @@ var _ = Describe("DriveItemPermissionsService", func() {
 			Expect(permission.GrantedToV2.User.GetLibreGraphUserType()).To(Equal("Guest"))
 		})
 
+		It("returns the guest id as stored by the share provider", func() {
+			cfg.Commons = &shared.Commons{EnableGuestLinks: true}
+			gatewayClient.On("GetUser", mock.Anything, mock.Anything).Return(getUserResponse, nil)
+			gatewayClient.On("CreateShare", mock.Anything, mock.Anything).Return(createShareResponse, nil)
+			driveItemInvite.Recipients = []libregraph.DriveRecipient{
+				{Email: libregraph.PtrString("Guest@\u0130nfocorp.com")},
+			}
+			createShareResponse.Share = &collaboration.Share{
+				Id:      &collaboration.ShareId{OpaqueId: "guest123"},
+				Grantee: guestGrantee("guest@xn--infocorp-o0e.com"),
+			}
+
+			permission, err := driveItemPermissionsService.Invite(ctx, driveItemId, driveItemInvite)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(permission.GrantedToV2.User.GetId()).To(Equal("guest@xn--infocorp-o0e.com"))
+		})
+
 		It("rejects guest shares when guest invites are disabled by default", func() {
 			driveItemInvite.Recipients = []libregraph.DriveRecipient{
 				{Email: libregraph.PtrString("guest@example.com")},
@@ -1477,3 +1495,12 @@ var _ = Describe("DriveItemPermissionsApi", func() {
 		})
 	})
 })
+
+func guestGrantee(mail string) *provider.Grantee {
+	return &provider.Grantee{
+		Type: provider.GranteeType_GRANTEE_TYPE_USER,
+		Id: &provider.Grantee_UserId{
+			UserId: &userpb.UserId{Type: userpb.UserType_USER_TYPE_GUEST, OpaqueId: mail},
+		},
+	}
+}