hoangnamitc Sounds to me like a cache or cookie issue. Please can you provide details of your environment as follows? :
- Flarum version: x.y.z
- Website URL: http://example.com
- Webserver: [e.g. apache, nginx]
- Hosting environment: [e.g. shared, vps]
- PHP version: x.y.z
- Browser: [e.g. chrome 67, safari 11]```
