Hi Becky and welcome to the community. It's always nice to see a new face around here.
I'm really sorry you're having some trouble with error code 7401 and a reboot hasn't resolved it. I'd very much like to get this sorted for you.
I've managed to locate your details and run some checks. There appears to be some issues with the downstream power levels which can result in this particular problem. I will drop a PM to you shortly (purple envelope top right) so we can arrange for an engineer to come around and resolve this for you.