It's not possible to delete snapshot of virtualbox
Result Code: E_OUTOFMEMORY (0x8007000E)
Because it's too big.
Delete snapshot files in the snapshot folder manually.
Release and remove from Virtual Box Disk Manager.
Reference.
How To Troubleshoot VirutalBox Out of Storage
https://www.nextofwindows.com/virtualbox-unable-to-merge-not-enough-free-storage-space