After Recode Friday confirmed a billing system outage at Verizon, the carrier on Saturday issued a statement explaining the issue: 

The Verizon Wireless billing system was fully restored early today, shortly after midnight. The issue affecting some customer access to account information was an unintended consequence of a software update performed by the company on its billing system two days ago. It affected customers mostly in the Northeast, Midwest and some southern states. This did not in any way involve the network’s ability to connect calls, deliver text messages or provide data services.  We apologize to our customers for any inconvenience they may have experienced and appreciate their patience.

A spokesperson for Verizon wasn’t able to provide more specific numbers about how many customers were affected by the outage. The outage prevented some customers from accessing their online accounts.

Frustration over the outage led to hashtags like #Verizonoutage and #Verizonfail popping up on Twitter, with many customers slamming the carrier and claiming on Friday that the outage was going on two days.