The following occurs a number of times;
A Kerberos Error Message was received: on logon session Client Time: Server Time: 4:18:21.0000 10/31/2016 Z
Error Code: 0x7 KDC_ERR_S_PRINCIPAL_UNKNOWN Extended Error: 0xc0000035 KLIN(0)
Client Realm: Client Name: Server Realm: DOMAIN.LOCAL Server Name: HTTP/archivemanager.domain.local
Target Name: HTTP/archivemanager.fms.local@DOMAIN.LOCAL Error Text: File: 9 Line: f0a Error Data is in record data.
Then the following occurs after ~14 occurrences of the above Application pool 'MSExchangeOWAAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool.