My Cloud EX2 fatal error code 4

Hello everyone
I have a my cloud ex2 taken at the end of 2020 on which I inserted a 12tb red wd hdd almost entirely full. I mounted another 16tb drive this evening to put on the raid. Since each option (I assume) provided for the formatting of both, I formatted the one from 16, removing the other first.
When I then put the saturated HDD back into my cloud, I was asked to roam or not. I accepted and now I find this notice on the one from 12.
The other remains empty …
What can I do to not lose the data of the small HDD?

You should try contacting WD’s Technical Support about this for live assistance and troubleshooting.

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