This is very old hardware and is not supported past 4.1, so it's very unlikely it's going to work for you on 6.5. See the HCL.
Then it's not being claimed by ESXi. List your version, your drive make and model, and the storage controller in use where it is connected.
How can I do that? Sorry, I am new to ESXi.
How do you list your ESXi version or information about your hardware?
version: 6.5.0 Update 1 (Build 5969303)
Dell Inc.
PowerEdge T105
4 CPUs x Quad-Core AMD Opteron(tm) Processor 1352
8 GB
0 B used, 0 B capacity
This is very old hardware and is not supported past 4.1, so it's very unlikely it's going to work for you on 6.5. See the HCL.
I think it is just the storage issue. Everything else seems to be OK.