Hi jammiedodger23
Thanks for your post, welcome to the Community Forums 🙂
Sorry to hear you've been having issues with your TV box since installation. From what you've said it doesn't sound like an issue with the HDMi or HDMi ports.
Have you checked to see if the coax is finger tight into the back of the TV box and isolator plate/splitter?
We can run some diagnostic checks on this side, however the TV box does need to be turned on. Please let us know once it is so we can view the status of it from here.
Many thanks
Beth