Huma Abedin, embattled former deputy chief of staff to Hillary Clinton, complained that her "clintonemail.com" account was malfunctioning in Aug. 2010.
In an email to Clinton that was recovered by the FBI during its original email investigation, Abedin apologized for the issues.
"Sorry. My email is acting up," Abedin wrote.
She went on to coordinate with Clinton how to approach a request from the king of Saudi Arabia.
Clinton has asserted repeatedly that she turned over all of her work-related emails. However, the FBI discovered at least 2,800 work-related emails that Clinton never provided to the State Department. Dozens of those were released by the agency Thursday.
Thousands of records discovered on a computer shared by Abedin and her estranged husband Anthony Weiner prompted the FBI last week to reopen its investigation of Clinton's private server.
Abedin has since disappeared off the campaign trail, although she is slated to co-host a fundraiser for Clinton Thursday evening.
The vast majority of the 1,250 pages of deleted emails made public Thursday were exchanges between Abedin and Clinton.