diff --git a/src/definition/App.ts b/src/definition/App.ts
index 8ed0515b0..6c2d442c1 100644
--- a/src/definition/App.ts
+++ b/src/definition/App.ts
@@ -58,7 +58,7 @@ export abstract class App implements IApp {
      * @return {string} the username of the app user
      */
     public getAppUserUsername(): string {
-        return `app.${ this.info.nameSlug }`;
+        return `${ this.info.nameSlug }.bot`;
     }
 
     /**
diff --git a/src/server/AppManager.ts b/src/server/AppManager.ts
index 58cef9592..eeb54669c 100644
--- a/src/server/AppManager.ts
+++ b/src/server/AppManager.ts
@@ -798,7 +798,13 @@ export class AppManager {
         return enable;
     }
 
-    private createAppUser(app: ProxiedApp): Promise<string> {
+    private async createAppUser(app: ProxiedApp): Promise<string> {
+        const appUser = await this.bridges.getUserBridge().getAppUser(app.getID());
+
+        if (appUser) {
+            return appUser.id;
+        }
+
         const userData: Partial<IUser> = {
             username: app.getAppUserUsername(),
             name: app.getInfo().name,