This error usually means that a VPN and/or another virtualization software, such as Hyper-V, are interfering with VirtualBox.
To fix it, please refer to:
If none of the above apply to you, and you can still launch Android 7.0 and below, your CPU probably does not support SSSE3.
Important
Android 8.0 and above require specific SSSE3 instructions, if your CPU does not support SSSE3, your computer will not be able to run virtual devices with Android 8.0 or above.
To verify whether your CPU supports SSSE3, please refer to https://en.wikipedia.org/wiki/SSSE3#CPUs_with_SSSE3.