Drobo 5C - I think I hosed it

For a few months my Drobo 5C was running out of space on a drive, so I replaced it this afternoon, swapped a 2TB for a 4TB. Drobo Dashboard said 45 hours to build, no problem. a few hours later Dashboard is telling me that there is a problem with the new drive, and to replace it. I pulled it out, the actually put it back in again. Immediately all the drive lights turned solid yellow, then the Drobo rebooted.

Now I only get a green power light, nothing else is lit, no drive lights, no nothing… just a green power light. What can I do here??? Can I unplug power then power it back up? Is it hosed???

Perform a basic restart first. Turn your Drobo and your PC/Mac off completely. Do not remove any HDDs. Restart both and see if you can re-establish connectivity and Drobo activity.

Do you have an external copy of your data?