From Fox News:
Federal law enforcement officials had notified congressional committees that a technical glitch affected thousands of FBI cellphones between Dec. 14, 2016 and May 17, 2017. This meant that 5 months' worth of texts would be missing from Strzok and Page, both of whom are under scrutiny after it was revealed that the former members of special counsel Robert Mueller's team exchanged anti-Trump texts during the 2016 presidential campaign.
Hannity said sources at the DOJ told him they have begun to recover some of the texts from that time period. Specific content from those texts has not been released.
The missing messages have caused problems for the Justice Department inspector general's office.
Senate Homeland Security Committee Chairman Ron Johnson, R-Wis., and Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, have sent a letter to Inspector General Michael Horowitz noting that the IG's office said on Dec. 13 that it had all the messages between Strzok and Page between Nov. 30, 2016, and July 28, 2017.
Lawmakers later learned of the five-month gap.