A friend brought me DVD that plays fine on my computer, but when I try to play it on my Sony DVD player, I get a notice that this DVD is not recognized/playable in this device (or words to that effect).

The original DVD was made with iDVD.

What did my friend do wrong?
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Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire