NTP servers can fail or transmit incorrect time information.

If an IT system can no longer reach its NTP servers because they have failed or are unreachable, it will no longer be able to adjust its system time. As a result, the system's internal clock time can become inaccurate.

If an NTP server transmits faulty time information to NTP clients, they may adjust their system clocks incorrectly. As a result, incorrect time information may be used in applications— for example, in log data.

Incorrect time information can also cause certificate-based services or services that use one-time passwords to stop working. This will prevent users from logging into affected IT systems or network services.