In a hallway of the all-Russian Museum of Decorative, Applied, and Folk Art in Moscow, I saw the pair of vending machines in the photo below.
The pink piece of paper over the coin slot on the second machine doesn't mean the machine is broken. There is a left arrow pointing to the other machine. The next photo is a close-up of the sign.
This means "All money for purchases should be put in the other vending machine". Seriously! You're supposed to select what you want in the machine on the right, then pay for it in the machine on the left, and then your product should become available to you in the machine on the right. I tried it and it worked.