Please tell me, sir, how to add a tag to my QQ account. Why can’t I find my post in that tag after clicking to join?

There are many reasons for your situation. Check them one by one according to the following methods.

First, confirm that the network is normal

Second, confirm whether you have published comments and pictures

Third, confirm whether visibility to friends is turned on

I suggest you use two of your own QQ accounts to add friends to each other and see if they can publish successfully? If you still can't publish, change your phone. If you can't publish anymore, your QQ is locked by the system. You can contact customer service to solve it.