No metrics returned

[rvsjoen]

Deployed in a docker swarm, container is running and trying to do something - logs are saying

monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:28:37.467Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:28:52.462Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:29:07.467Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:29:22.456Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:29:37.444Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:29:52.459Z caller=collect.go:147 monitoring_sendgrid-exporter.1.vkabhrbmkikq@foobar-cloud-manager01 | level=error ts=2023-01-18T14:30:07.455Z caller=collect.go:147

The following command returns nothing
$ curl localhost:9154/metrics

And the health check is OK
$ curl localhost:9154/-/healthy OK

sendgrid-exporter is running with log level debug but doesn't seem to output anything more than error/info level

/bin/exporter --web.disable-exporter-metrics --sendgrid.api-key='SECRETKEY' --log.level=debug

Are there any tricks to make it tell me why it is not outputting anything ?