Fidelity National Financial, or FNF, a Fortune 500 company that provides title insurance and settlement services for the mortgage and real estate industries, announced on Tuesday that it was the victim of a “cybersecurity incident that impacted certain FNF systems.”

The company filed a report with the Securities and Exchange Commission (SEC) saying that it has launched an investigation, hired “leading experts” to help, alerted law enforcement and “implemented certain measures to assess and contain the incident.”

“Among other containment measures, we blocked access to certain of our systems, which resulted in disruptions to our business,” the report read, adding that this affected services related to title insurance, escrow, other title-related services and mortgage transactions.

“Based on our investigation to date, FNF has determined that an unauthorized third party accessed certain FNF systems and acquired certain credentials. The investigation remains ongoing at this time,” the report read.

FNF did not respond to requests for comment.

Real Estate News reported that the breach stopped scheduled closings, which left agents and homebuyers “scrambling for solutions” as they have been told that the systems needed to complete their transactions won’t be available until Sunday.

A person who said they work at a company that does business with Fidelity Financial Services, and has knowledge of the incident, told TechCrunch that they heard FNF “decided to shut down their network, systems, and even their email […] in an attempt to scrub their servers in Jacksonville and prevent any issues.”

Another source, who said they worked in IT for a company that uses FNF, told TechCrunch that they heard FNF was “all locked up.”