HTTP 500 error is generic, and so it's very difficult to know exactly where it's coming from.
In order to do so, I would first check that all my TDM services are running well (CA Remote Publish, CA TDoD), then check that my test match is already running well from Datamaker (remove all source of errors, except portal).
Then, push logs to DEBUG level (update TDM portal configuration file logback-tdm.properties). This is also documented here Enable DEBUG mode. After that, stop TDM portal, delete all logs and restart, and do your test match again.
You should now have more information to understand when and why it fails.