"Groupon's mission is to deliver the best deals on the planet for the things our customers want, and Starbucks is a brand our subscribers crave," Julie Mossler, a Groupon spokesperson wrote in an e-mail that didn't directly address a question as to whether the promotion was experiencing technical difficulties.
After Groupon tweeted out the Starbucks offer, the company received a handful of complaints from users who were frustrated in efforts to access their purchases.
"Sorry for the trouble -- we're working fast to fix the problem! We'll be back at full strength soon," responded @GrouponLA, a verified Twitter account for Groupon's Los Angeles businesses.
The overwhelming majority of tweets referencing the Starbucks Groupon were positive. "Holla!" wrote @caryplunkett. Starbucks' arrangement with Groupon follows a similar promotion from Living Social, which recently got an investment from Amazon (AMZN).
That deal, according to LivingSocial, generated about 1.5 million purchases and was the site's best-selling offer. The coffee deal represents the first between the two companies since Starbucks CEO Howard Schultz stepped down from Groupons board in April. Friday's Groupon may help Starbucks fuel its own push into mobile transactions.