Hello Robert,

You should be able to change nameservers at NetworkSolutions without any issues. I recommend opening a ticket with us. Please provide us with nameservers you try to set at your domain registrar and we will verify if it is correct.

If you are using your private nameservers, there is a chance they didn't propagate yet and registrar doesn't accept their usage for some reason. If you use nameservers that were sent to you in the welcome letter, everything should be smooth.

Anyway, it would be great if you could open a ticket specifying the domain name and nameservers you try to set, it would be great.