There is an intermittent issue, still to be diagnosed by Microsoft, where the bundled SQL Server driver can fail to properly communicate with the database.  

  This error affects multiple database versions, and is documented with SQL Server 2016 and SQL Server 2019.

This error is seen in the logs, and the UI gives a 500 Internal Server Error:

Caused by: com.atlassian.activeobjects.internal.ActiveObjectsSqlException: There was a SQL exception thrown by the Active Objects library:
Database:

name:Microsoft SQL Server
version:15.00.4395
minor version:0
major version:15
Driver:
name:Microsoft JDBC Driver 9.2 for SQL Server
version:9.2.1.0

com.microsoft.sqlserver.jdbc.SQLServerException: The TDS protocol stream is not valid. Unexpected token unknown token (0xA3).  

The solution is to update the driver to 11.2.  Here is the fix release for JDBC regarding the token error https://learn.microsoft.com/en-us/sql/connect/jdbc/release-notes-for-the-jdbc-driver?view=sql-server-ver16#fixes-in-112 .