Improve error message for checking claims.Audience

backend/app/cmd/server.go

@@ -1215,6 +1215,7 @@ func (s *ServerCommand) getAuthenticator(ds *service.DataStore, avas avatar.Stor
 			if c.User == nil {
 				return c
 			}
+			// Audience is a slice but we set it to a single element, and situation when there is no audience or there are more than one is unexpected
 			if len(c.Audience) != 1 {
 				return c
 			}

backend/app/rest/api/admin.go

@@ -107,8 +107,9 @@ func (a *admin) deleteMeRequestCtrl(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Audience is a slice but we set it to a single element, and situation when there is no audience or there are more than one is unexpected
 	if len(claims.Audience) != 1 {
-		rest.SendErrorJSON(w, r, http.StatusBadRequest, fmt.Errorf("bad request"), "can't process token, aud is not a single element", rest.ErrActionRejected)
+		rest.SendErrorJSON(w, r, http.StatusBadRequest, fmt.Errorf("bad request"), "can't process token, claims.Audience expected to be a single element but it's not", rest.ErrActionRejected)
 		return
 	}
 

backend/app/rest/api/admin_test.go

@@ -847,7 +847,7 @@ func TestAdmin_DeleteMeRequestFailed(t *testing.T) {
 	b, err = io.ReadAll(resp.Body)
 	assert.NoError(t, err)
 	assert.NoError(t, resp.Body.Close())
-	assert.Contains(t, string(b), "can't process token, aud is not a single element")
+	assert.Contains(t, string(b), "can't process token, claims.Audience expected to be a single element but it's not")
 	badClaimsMultipleAudience.RegisteredClaims.Audience = jwt.ClaimStrings{"remark42"}
 }