His Twitter handle was silent until after the game, when he sent out a series of tweets  beginning with: "Att crashed ... ahhhh!!!! The worse."
An AT&T spokesperson did not immediately return a call from The Associated Press on Sunday night.
He said in an interview after the performance that his favorite moment of the halftime show was when the band took the stage by being lowered from the ceiling.
"We were getting beamed down like we came from another planet," he said. The band sang hits including the party anthem "I Gotta Feeling," "Pump It" and "Boom Boom Pow." They were also joined on stage for brief appearances by former Guns 'N Roses guitarist Slash and Usher.
The Peas' frontman, will.i.am, sent several tweets before the show, including one that said, "My butterflys are flying around like crazy."
After lamenting the cell service during halftime, will.i.am started tweeting again. One message said, "That was so freakin sick ... wow ... !!!"
"I'm feeling like I'm on top of the world," he said after the performance. "It was fresh man," he said. "It felt like cinematic."
He said performing the show with his fellow band members - Fergie, Taboo and apl.de.ap - was an emotional experience.
"Playing this show just showed what you can do when you believe in a team," will.i.am said.
He also was excited about the Super Bowl commercials because he directed the two TV spots that were shown before and after the live performance. He created and directed the commercials for Chatter.com.
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