The time service has not synchronized the system time for 86400 seconds

Why would we see the following on Windows Server 2016 Standard Edition?

Log Name:      System
Source:        Microsoft-Windows-Time-Service
Date:          16/10/2017 02:48:22
Event ID:      36
Task Category: None
Level:         Warning
Keywords:      
User:          LOCAL SERVICE
Computer:      %computername%.domain.suffix
Description:
The time service has not synchronized the system time for 86400 seconds because none of the time service providers provided a usable time stamp. The time service will not update the local system time until it is able to synchronize with a time source. If the local system is configured to act as a time server for clients, it will stop advertising as a time source to clients. The time service will continue to retry and sync time with its time sources. Check system event log for other W32time events for more details. Run 'w32tm /resync' to force an instant time synchronization.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Time-Service" Guid="{GUID}" />
    <EventID>36</EventID>
    <Version>0</Version>
    <Level>3</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2017-10-16T01:48:22.423879700Z" />
    <EventRecordID>416872</EventRecordID>
    <Correlation />
    <Execution ProcessID="3736" ThreadID="6620" />
    <Channel>System</Channel>
    <Computer>%computername%.domain.suffix</Computer>
    <Security UserID="S-1-5-19" />
  </System>
  <EventData Name="TMP_EVENT_TIME_SOURCE_NONE">
    <Data Name="UnsynchronizedTimeSeconds">86400</Data>
  </EventData>
</Event>