Configure Cloudwatch as Source

https://grafana.com/docs/grafana/latest/datasources/aws-cloudwatch/

• SerializationError:failed to unmarshall response error status code: 404 ... failed decoding error message 000000 ... by: invalid character

Solution: review optional endpoint configuration is correct, you can try to remove it as it optional. 

See also

• Grafana, Grafana datasources, Grafana Alerting, Grafana installation, Grafana Labs, Grafana Changelog, Grafana logs, docker-compose.yml (Grafana), Grafana Loki, Grafana Tanka, StatsD and Graphite, grafana-cli, Loki, LogQL, Grafana Enterprise, Grafana Cloud, Grafana alerts, Amazon Grafana, Grafana OnCall, Grafana Tempo, Grafana Mimir, Grafana agent, plugins, Terraform, Grafana dashboards, /etc/grafana/grafana.ini, Grafana Pyroscope