-2006F

Given the lack of information all I can guess is:

Spinning globe

If you see a spinning globe instead of an Apple logo, it means your Mac is starting from a network-based startup disk like Netboot or Internet Recovery instead of a connected or built-in startup disk. If you didn't mean for your Mac to start this way, press and hold the power key to turn off your Mac. Then, press the power key again to start up normally.

If your Mac always starts to a spinning globe and you're at a school or business, check with your IT department for more information. There might be a server on your network that your Mac is trying to start from. If this is your personal Mac, try starting from macOS Recovery to check your startup disk and macOS.

I got from: About the screens you see when your Mac starts up - Apple Support

in Internet Recovery, these low negative thousands error messages indicate that your provided Wi-Fi Network is inadequate in some fashion, and cannot be used in its current state.

Common problems include:

Hidden Network-name

required use of a proxy server to get Internet access

required use of a login page to get Internet access

Use of a login server or certificate to get Internet access

Use of PPPoE in the Mac to get Internet access (typically only applies to DSL)

Use of Fixed IP address rather than good old DHCP

Variance of the time by more than five minutes

Failure of Router to provide workable DNS server addresses, or providing 0.0.0.0 [may produce -2002f]

If you have an Ethernet port, you may in some cases be able to move your Mac close to the Router and connect to the Router using Ethernet.

The higher the number, the more obscure the problem.

Try macOS internet recovery >. About macOS Recovery - Apple Support

Context?

What model/year computer? What operating system? What apps were running? Any other symptoms? Any new updates? Any new apps?