Event ID 6398 due to CEIP Data Collection for SharePoint Foundation:
This issue can occur because of a failed job CEIP Data Collection for SharePoint Foundation.
Error 503 Service Unavailable while browsing SBS Web Sites:
Error 440 Login Timeout While Browsing OWA:
When SpecialPollInterval is used as a polling interval, the Windows Time service does not correct the time if the service gets into Spike state: