diff --git a/src/app/services/util/topic-cloud-admin.service.ts b/src/app/services/util/topic-cloud-admin.service.ts
index 2eb50526ba23d6c965d51cbb8444d610682d1469..85e45e36d6cc29d36ab5d2687ed5c1f1394b8208 100644
--- a/src/app/services/util/topic-cloud-admin.service.ts
+++ b/src/app/services/util/topic-cloud-admin.service.ts
@@ -112,7 +112,7 @@ export class TopicCloudAdminService {
   addWordToBlacklist(word: string) {
     if (word !== undefined) {
       this.getRoom().subscribe(room => {
-        const newlist = JSON.parse(room.blacklist);
+        const newlist = room.blacklist ? JSON.parse(room.blacklist) : [];
         if (!newlist.includes(word)){
           newlist.push(word.toLowerCase());
         }