Not sure about the full scope of what you attempted via "manually trying to connect" (e.g., wired connection perhaps).
However, in any case, more information is needed.
Make & Model USB adapter? Does it feel overly warm or even hot? I have had a couple fail on me and the "heat" is often quite noticeable.
Do other wireless devices use/detect 5 GHz?
I would start by downloading the applicable wireless adapter drivers and reconfiguring the adapter as applicable to your wireless network.