Error "support.apple.com/mac/startup" on MacBook Pro

-2100F

In Internet Recovery, these low negative thousands error messages (between -1000 and -7005) indicate that your provided Wi-Fi Network is inadequate in some fashion, and cannot be used (for this purpose) 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. if your battery has run flat, the time will likely be wonky and have to be specified with a Terminal command

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.

A globe with a warning symbol (exclamation point) means that your Mac tried to start up from macOS Recovery over the internet, but couldn't. Learn what to do if you can't start up from macOS Recovery.