Justin Bieber canceled his second show in Portugal, and it had nothing to do with health problems or paparazzi beatdowns.

Instead, it could be for a reason with which he's entirely unfamiliar: a simple lack of interest.

Of course his manager denies this, but multiple sources, including the generally reliable TMZ, is on Team Unsold Tickets -- so there may very well be some truth to the story.

The site says pulling the plug on the second Portuguese show this week was a "business decision," and that while more than 60 percent of the seats sold, that just wasn't good enough for the Biebs -- who's accustomed to sold-out crowds (like the four he had during his eventful stay in London last week).

All of this started when the UK tabloid the Mirror cited a Portugese newspaper that reported "there had not been enough demand for tickets."

But his manager Scooter Braun told GossipCop that's not true. He claims both Lisbon shows, scheduled for Monday and Tuesday, March 11 and 12, were sold out, but there were problems with the time needed to break down the stage and the equipment. Hence, the second show was wiped off the schedule.

As for the Mirror, Braun replied, “The British tabloids are full of s---.” Because apparently that's how grownups with superstar clients talk to the media these days.

Early Monday, Justin's Twitter feed was uncharacteristically silent on the canceled show, but he did send out a missive that ensured everyone would know that the first Lisbon concert, at least, will be well-attended.