Apple TV audio; no dialogue audio but background music and sound effects can be heard

Hello,

A family member, with whom I use Family Sharing for subscriptions and access to my library has traveled to Ireland for a few months. They are trying to watch “Bad Sisters” through my Apple TV + subscription and can hear background music and other sound effects but no dialogue is audible.

They uninstalled and reinstalled the app on their phone with no luck.

Any troubleshooting ideas to hear the audio for dialogue?

Thanks!