Why start power of machine in Oracle VM Virtual box fails with code 0x80004005?

I standardly power off virtual machine in Oracle virtual server (so other VM can run). When I tried to start it again I end up with E_FAIL (0x80004005).

Failed to open a session for the virtual machine Enterprise portal.
No error info.
Result Code: E_FAIL (0x80004005)
Component: ProgressProxy
Interface: IProgress {c20238e4-3221-4d3f-8891-81ce92d9f913}

Only advice I was able to find was "disabled the Network adapter" which I tried (I disable network settings of virtual machine) and it does not help.

How I can start it?