Hi,
External calls displayes the contents of BillableCalls table in database, there is a timer that should be moving from raw data (generated by kamailio and cgrates) to that table.
Check ivozprovider-scheduler.timer is running and check any possible errors in ivozprovider-scheduler.service (using journalctl)
You can also try removing scheduler cache located at /opt/irontec/ivozprovider/microservices/scheduler/var/cache/prod/
You can also manually run the migrator by running /opt/irontec/ivozprovider/microservices/scheduler/bin/run-billable-calls but be sure there service is stopped to avoid processing the same data twice.
Best regards,
Kaian