SharePoint Pain

Applies to SharePoint 2016; not tested on other versions of SharePoint.   Symptoms   Windows Application Event Viewer shows two certificate-related errors every minute as follows:   Event ID 8306   An exception occurred when trying to issue security token: ID3242: The security token could not be authenticated or authorized..   Event ID 8311   An operation failed because the following certificate has validation errors:   Subject Name: CN=SharePoint Security Token Service, OU=SharePoint, O=Microsoft, C=US Issuer Name: CN=SharePoint Root Authority, OU=SharePoint, O=Microsoft, C=US Thumbprint: 8C0669A6945F6A310538F1F8159D541CBDFE9427   Errors:   PartialChain: A certificate chain could not be built to a trusted root authority. RevocationStatusUnknown: The revocation function was unable to check revocation for the certificate. OfflineRevocation: The revocation function was unable to check revocation because the revocation server was offline. ...

Applies to SharePoint 2016; not tested on other versions of SharePoint.   Symptoms   SharePoint Central Admin’s Health Analyzer shows "Drives used for SQL databases are running out of free space". For example:     Cause The value of Autogrowth for the database files are not set optimally for the free disk space that the Health Analyzer calculates. For example: Resolution   Set the Autogrowth to the correct value . Do not use a percentage or a non-binary unit as a fixed value. Inform the DBA. For example:       Note: - The Health Analyzer Rule Definition and the Error Status pages look very similar and share the same title, "Drives used for SQL  databases are running out of free".  Make sure you're looking at the right page by checking the URLs (../Lists/HeathRules/... vs. ../Lists/HealthReports/...) and the Ribbon: -   For getting into the depth of the error and calculating the correct value, you can refer to  https:/...