Fix AWS RDP Authentication Issue -- 2

I have a AWS Server running Windows 2012R2. Today I changed 2 group policy settings i.e.

-Accounts: Limit local account use of blank passwords to console login only - disabled
-Network access: sharing and security model for local accounts to Guest only

After I restarted the server I am unable to connect to the server using RDP. This happened because of the group policy settings that I changed. Since I cant connect via RDP I cant revert changes.

When I try to connect it gives error: "An Authentication Error has occurred. The local security authority cannot be contacted. This could be due to expired passwords. Please update your password if it has expired."

I have 2 user accounts (admin & standard) and both have passwords.

Please help me fix the issue so that I can use RDP to login again.

Apply if you know exactly what needs to be done to fix the problem. Please do not experiment.

Ideal Skills and Experience:

- Must have solid experience in troubleshooting AWS EC2 instance connection errors.
- Strong understanding of Windows Server Operating System.
- Knowledge on resolving RDP authentication errors.
- Experience with AWS connection via other means

Thank you