Lots of inactive sessions causing DB server outage

We've got a Oracle database with only one application as client. The app is connecting to DB through UCP with OCI driver. We have set all available paramenters in pool as follows:

             abandonedConnectionTimeout="60"

             inactiveConnectionTimeout="60"

            maxConnectionReuseTime="60"

            maxIdleTime="60"

Also we have configured sqlnet.ora configuration file with SQLNET.EXPIRE_TIME = 10 both server and client side and activated idle_time in profile as follows:

alter profile default limit idle_time 10;

After all of this setting, we still have connection issues because inactive sessions do not stop growing and, after some time, we need to restart applicacion to release datbase connections/sessions.

Datasource statistics does not show any problem (I migth be worng):