Hi sb88
Thanks for dropping by with your post about the error code 7400 on your TiVo® service and a warm welcome to the community 
My apologies that the service was affected when you posted to us last week.
Do you still have the same issue? If so if you could reboot your TiVo® for us again as some signals have been sent to help correct this for you.
If after the reboot this is still unresolved if you could let us know as it would then mean booking an engineer for you.
Keep us posted and if there is anything else we can help with, just give me a shout