谢谢大家，我把operational ratel 的低速率从disabled调整为Mandatonry开启就可以了。

I set the 2.4g profile in RF to Global config and it connects fine, is there any difference in this default configuration? 

Another phenomenon is that it can't search the 2.4g in the warehouse of building A, but it can search it when it gets to the warehouse of building B. Building B uses another AP model from Cisco , on another AC.

The ap mode that can search for wifi signals is local, and the one that can't is flex.