Registering DOIs fails with DataCite plugin

Kia ora folks,

I’m trying to register our DOIs with the DataCite Fabrica Test website (not production) using our dev. OJS environment. I keep getting a “Registration was not successful! The DOI registration server returned an error: ‘Registering DOI 10.80170/howtov0i3: 404 - Not found’.” error.

We are using:
OJS - version
DataCite plugin - version (enabled and configured)
DOI plugin - version (enabled and configured)
Prefixes - 10.80170 registered and tested using the DataCite Fabrica Test website.

Does anyone have any experience in fixing such and error? Does anyone know if the OJS plugins export successfully to the DataCite Fabrica Test website?

Nga mihi,