You have protected the guest machine and enabled self-protection. When you try to remove the self-protection in the said guest machine using "dsa_control -s=0" command, the process will initiate but it will eventually shows the following error:
HTTP Status: 403 - Forbidden - Untrusted peer
This issue happens regardless whether you have used a password or not.
To properly unharden the guest machine, use one of the following commands:
- dsa_control.cmd -m -p x#x#x#x#x#
The "x#x#x#x#x#" part should be replaced with an appropriate password.
- dsa_control -m -p *
This command will prompt for password.