Just to add to what @schnapps has said have you tried swapping HDMI cable? @Anonymous User I remember seeing an issue very similar to this a few days ago and that was resolved by swapping the cable unfortunately they don't last forever, especially the cheaper cables.
that being said, so don't go buying an expensive goldplated one or anything like that . they charge five times a price that they should for them and you don't need anything fancy like that. It's just a data cable at the end of the day.
I do not work for Now . I am simply a Now customer trying to help I am a Community Contributor This means that I know a lot about the service. But just like you I am still a customer. This means I cannot help you with issues that would involve looking into your account directly. A member of the now TV forum team or live chat will need to assist you with these issues.