wifi network driver issue

Hi my router is dual band and 5ghz works on other laptops but my Dell Inspiron 15 will only connect to the 2ghz and not the 5ghz.

The drivers are all up to date and is a dual band network adapter:Qualcomm-QCA61x4A-QCA9377-Wi-Fi-and-Bluetooth-.

I have specified 5ghz as my preferred band and also put the roaming aggressiveness to its highest level via the advanced tab of the network adapter properties but it still only connects to the 5ghz .

Any help would be much appreciated.

Thanks