While the system is able to register your computer almost instantly, the network database takes approximately fifteen minutes to update. Be sure to wait fifteen minutes AND then restart your computer.
(For those of you with more technical experience, one of the purposes of restarting the computer is to ensure that the computer's DHCP lease is renewed. If that sentence doesn't make sense to you, please feel free to ignore it.)
If your connection does not work after several hours, Submit a Request for help. You can also go to the My Network Registrations Page and review the information submitted in your registration to ensure its accuracy and make sure that you selected the appropriate choices. Two common mistakes are (1) putting a wired ethernet (MAC) address in a field designed for a wireless address, or vice versa, and (2) identifying a device as "other" instead of a more appropriate category (i.e. laptop, desktop, etc.).