The config sol.kerberos.login.conf seems to be no effect in solace_source.properties

[pape2016]

I want to use connector to connect to solace service with kerberos authentication. so I uncomment kerberos configuration options and set values:

sol.authentication_scheme=AUTHENTICATION_SCHEME_GSS_KRB
sol.kerberos.login.conf=/connectors/login.conf
sol.kerberos.krb5.conf=/connectors/krb5.conf

Then I start the connetor but failed with exception [No LoginModules configured for SolaceGSS]

It looks like connector doesn't find login.conf, as after I comment the configuration of login.conf, connector starts with the same error.
Then, I modify the shell script of Kafka: bin/kafka-run-class.sh
add below arg in java execution path at the end of the shell script file:
-Djava.security.auth.login.config=/connectors/login.conf
like this:

exec "$JAVA" #KAFKA_HEAP_OPTS -Djava.security.auth.login.config=/connectors/login.conf $KAFKA_JVM_PERFORMANCE_OPTS ......

Then, the connector start success.!

I confuse why the login.conf can not be found if it is configured in solace_source.properties, and can be found if I put it in java execution path directly.

[pape2016]

Besides, sol.kerberos.krb5.conf is ok to get it from solace_source.properties, so it is a little weird why sol.kerberos.login.conf is not working.