I can only watch first episode of a four part series on apple tv

With the Apple TV app on your smart TV or third party streaming device, you can access:

• iTunes Store movies and TV shows (buy or rent);
• Apple TV+ channel featuring Apple Originals [1] [2], by subscription;
• other premium Apple TV app Channels, each by subscription.

Can you disclose what you were trying to watch?

What happens when you try to watch episode 2? Do you get an error message? What does it say?