How to solve this problem?

Do you have cable or an antenna?

Are you using antenna? I antenna mounted outside and high on a pole usually get better reception/more channels. Have you turned the antenna? Different antenna positions pick up more or less signals. Some people use an amplifier also to increase signal strength. If you have a service like Sling the problem could be your router not being close enough to the tv set or something physically blocking the signal. Even moving the router a few feet can make a huge difference.

What type of service do you have? Cable? Satellite? Back in the day before we had so many options, everyone had some sort of antenna on their homes.

If you don't have cable you can get one of these to increase the signal

https://www.homedepot.com/p/Inland-Slim-Indoor-Antenna-05500/207007710?MERCH

If your just using a digital antenna placement of the antenna is crucial. Also depends where the transmission station is. I cut the cord and bought an RCA digital antenna and was getting about 50 channels. A lot of them were really bad. I eventually went online and made my own antenna. With it I ended getting 87 channels and great reception. Here is a site to check what channels are available where or near where you live.

https://www.fcc.gov/media/engineering/dtvmaps

If you have satellite TV, the signal might be blocked by any trees, brushes or any other object. You will need to call the satellite company and have them come out (for free) to check the site to see if there is any interference.

I can recommend to buy and use IPTV. For example look set-top boxes from Infomir company, very cool devices that provide many options. For example MAG254 is good and modern device https://www.infomir.eu/eng/products/iptv-stb/mag255/. I'm sure you will be able to watch your TV shows or films in great quality.