"Usher Suspected of Ruining Concert Due to Substance Abuse"

What do we have here?
Some of you may remember that Usher’s PR team said their client had to cancel his Berlin tour date due to some mysterious illness earlier this week. Well, Ursh’s fans aren’t buying it. One of his German fans sent a letter to YBF, informing the popular web site that Usher was seen at a cocktail bar hours after the show he canceled. Read the letter below.

Hey Natasha!
I’m from Germany and I’m pretty sure that almost none of you heard about the BIIIIIIIIIIG Usher scandal in Germany. Yesterday, Usher had his first show of his OMG Tour in Germany/Berlin and after the previous artist, Tinie Tempah, fans waited more than 40 minutes until the management cancelled the show because Usher “wasn’t feeling well” and they postponed it to today.
It is also said that he was seen in Berlin in a Cocktailbar after cancelling the concert! His fans had to wait about 40 more minutes today until he came on stage. There were five songs (sung only playback not live), interrupted by several 5-minute breaks during which Usher left the stage without further announcements and a “DJ” took over for a few minutes.
Then the fiasco took its course: as Usher sang a song which he sang “wrong and crooked”, he interrupted the song and gave an excuse for the cancellation of the previous day. While trying to sing everybody booed at him.
Usher’s reaction: he sat down and put his head on the microphone. After he had sung for another 10 seconds, he went off the stage. The lights went on and the concert was over. Fans from all over Germany, Austria and other countries came to see him and then something like this happened. No one knows exactly what happened, if he’s really ill or if he took drugs, too much alcohol. I thought this might be interesting for you and sorry for my bad English!
Clips of his Berlin performance have been circulating online and he definitely looks out of it. The guy’s just standing there looking incapacitated. [Watch Here]
I’m not gonna speculate on what I think went wrong. I’m sure we’ll find out eventually. What do you guys think? What went wrong with Usher’s performance?  SOUND OFF!