Another day of SharePoint fun!
DBA changed a service account password, then failed-over the cluster to a different node. Roughly one hour later, one of the WFE boxes pegged the CPU at 100% for an extended period of time. We also run KnowledgeLake, and the search web part would not load.

First, I directed our load balanced traffic to another WFE box. Once all the open connections were closed, I fired off an iisReset. This alleviated the CPU load.

BUT, the KnowledgeLake web part would not load AND the logs on one of the app servers had the below errors.

Fix? After hours I rebooted the app server in question. Errors stopped appearing and the KnowledgeLake web part loaded.

Unknown SQL Exception -2146893055 occurred. Additional error information from SQL Server is included below.

A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: SSL Provider, error: 0 – The handle specified is invalid)

Event ID 5586

Cannot connect to SQL Server. ServerName not found. Additional error information from SQL Server is included below.

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

Event ID 3355

SQL Database ‘WSS_Logging’ on SQL Server instance ‘ServerName’ not found. Additional error information from SQL Server is included below.

Cannot open database “WSS_Logging” requested by the login. The login failed.
Login failed for user ‘domain\webAppAccount’.

Event ID 3760