I want to connect to my verizon jetpack and have a gateway mx6426?

You might want to try this on your computer. First, remove a wireless network via Control Panel > Network and Sharing Center >Manage Wireless Networks in the left pane and right-click the one you want to remove.

Once it is removed try to log onto the network again, it will ask you for your password which should be on the back of the device underneath the battery or on a sticker on the back.

If that doesn't work you may want to try and call technical support. They can walk through some additional steps to identify the problem.