This incident has been resolved.

We are continuing to monitor for any further issues.

The test server ran out of memory and stopped responding; we restarted it, and it's working again. If you had problems depositing or querying in the test system during this time, please try again. We'll monitor. -GH

The test admin system has been down since about 09:30 UTC, so members will see a 503 Service Unavailable message when visiting test.crossref.org. We're investigating. -GH