Uber apologized Monday after its support Twitter account tweeted the n-word. The tweet was in response to a Twitter user who adopted the slur as their username and then tweeted at the support account, apparently in a deliberate attempt to get Uber to tweet the word.

We’d like to sincerely apologize for the offensive tweet that was sent earlier. We’re investigating what happened to make sure it doesn’t happen again.

— Uber Support (@Uber_Support) April 29, 2019

“We apologize for this offensive tweet and are disappointed our process to prevent something like this from happening was not effective here,” an Uber spokeswoman said in a statement emailed to Fast Company. “Our support team is taking additional steps to help ensure this doesn’t happen again.”

She didn’t respond to inquiries about what “additional steps” the company is taking or to what extent automated processes were involved. The initial tweet appeared to encourage the complaining user to shift the conversation to a direct message with details and addressed the user by the slur. Uber has at times faced criticism for providing uneven levels of support to riders and drivers.

The embarrassing moment happened at a crucial time for the ride-hailing giant, which just launched its IPO road show. The tweet also highlights how automated processes that insert user-provided information can be vulnerable to malicious or misinterpreted data, whether it’s programming code designed to disrupt processes or simply offensive language.

While it’s common for customer support and marketing messages to address customers by name, especially when they’re sent by automated processes, it’s also common for Twitter users to adopt nicknames, punny or culturally referential first names that a savvy human would know not to use.

Still, even humans can mistake the fake names for real ones. For example, the award-winning New York Times writer Nikole Hannah-Jones uses the name “Ida Bae Wells” on Twitter, a reference to the journalist Ida B. Wells, known for her coverage of lynchings in the 1890s. Not everyone gets the reference, she’s tweeted.

The Times itself also had to issue a correction in 2013 after referring to writer and activist Jillian C. York as “Chillian J. Yikes,” which the paper noted was a Twitter “pseudonym she created for Halloween.”