Hi @kongyc870320
Could you see this post and try if the solution there will work for you?
I just noticed that in your original post, you’ve stated your server URL as https://chat.3lc.my:8065/. However, when I tried that link, it’s not reachable. I’m able to connect at https://chat.3lc.my/ that is without port 8065. Could you confirm if you’re able to connect on Android to https://chat.3lc.my/?
UPDATE: Add link to post mentioned - Mattermost Android App (1.8.0) not starting up