How do I enable the 2.4 GHz band on my AT&T router?
Transponder. When you log into your 5268ac, go to the LAN menu then WIFI. There at the top of that menu you will see the very first item is 2.4 ghz wifi interface disable or enable. Make sure it is enabled. If it is already enabled, change it to disabled then save the settings near the bottom of the page.