Not to worry if all the spots were snatched up before you could get through. All of the attractions that utilize a virtual queue have a second booking window in the afternoon.
For Disney World, you can try again at 2 p.m. for a Rise of the Resistance boarding group, but you do have to be inside Hollywood Studios for it to work. Other than that, the process is the same.
For Disneyland, you can make a second attempt at noon for Web Slingers or Rise of the Resistance. You do have to be inside one of Disneyland's two parks, but it doesn't matter which one. As long as you have a Park Hopper ticket, you can head from one park to the other if need be when it's your time to ride.
Because Disneyland currently has two attractions that use a virtual queue, you could technically get a boarding group for both rides if you get one in the morning and one at the noon drop. You can't hold two virtual-queue spots at one time, so you would need to have ridden your first ride before the second virtual queue opens. Don't get your hopes up, but it is possible.