Error creating a new datastore

Hello,

on an esxi 6.7.0 Update 3 (Build 14320388) I did deleted the datastore residing in same disk as the esxi has been installed, then I tried to create a new datastore using the free space left after deletion (the reason is a change of format type, from vmfs6 to vmfs5).

Trying to create the new datastore using the provided procedure, I correctly see the disk:

then, when I select the free partition, set it to vmfs5 and then move the slider to full space available, this is what the procedure shows me:

and this happens when I click on finish:

I just suppose the partitions have been used incorrectly, but any help here is very appreciated, to understand how to correctly create the new datastore.

Thanks in Advance!

Andrea