Can't Find mySQL connector

I downloaded 3.8.1 JPA-Guice zip and installed it on an AWS linux EC2.  
I downloaded the latest mySQL JDBC connector and put the jar in 
external-jars.   When I start up James, I get several exceptions saying 
it can't find com.mysql.cj.jdbc.Driver.  I tried moving the connector 
jar into james-server-jpa-app.lib.  No change. I haven't yet upgraded 
the database mySQL 5.7 to mySQL 8. Is this the problem?  It seems pretty 
straight forward when the error message says java can't locate a class.  
But the class is in the jar file and the jar file is in the same folder 
with all of the other jars.  Do I have to add this jar to a classpath 
somewhere?  What am I missing?

thx

Jerry