John has a home theater made by Samsung, and he's having issue playing Blu-rays. Leo says it's possible that copy protection is causing it to not be able to play because his player isn't connected to the internet. If it's not connected to the internet, it assumes the Blu-ray's key has been revoked, even when it hasn't been.
John should change out his cable for his Blu-ray player. That could be causing it. A dead or faulty cable can cause the HDCP copy protection issues as well.