Nighthawk MR6500 won't connect to 5G on AT&T

While many questions about routers are generic and could be answered anywhere, some things need specialist knowledge.

You might get more help, and find earlier questions and answers specific to your device, in the appropriate section for your hardware. That's probably here:

Mobile Routers, Hotspots & Modems

Those things are very different from the standard Netgear routers covered in this section.

You might like to search there for messages related to your problem.

I will ask the Netgear moderator to move your message.

In the meantime you could visit the support pages:

Support | NETGEAR

Feed in your model number and check the documentation for your hardware. Look at the label on the device for the model number.

Check for various troubleshooting tips.

You may have done this already. I can't tell from your message.

I mention it because Netgear stopped supplying printed manuals and CD versions some years ago and people sometimes miss the downloads.

Usually its the one that att gives you for setting up hotspots. 

Did you check with them?