No suitable driver for the connection

Neo4j Desktop V4.2.3 and Neo4j ETL Tool.
Under "Choose Files" have placed the mssql-jdbc-8.4.1.jre8.jar file for MS SQL Server V2017.
The message "No suitable driver for the connection" is always returned, no matter which JAR file.
The connection string ijdbc:sqlserver://localhost\sqlexpress:1433;databaseName=meterreadings