MacBook error message 2002F

Try doing an NVRAM reset as this alone will often flush things out allowing you to get into Internet Recovery.

If that doesn't work, and you previously had any macOS on there from 10.13 High Sierra or higher, use the Shift-version of Internet Recovery (Shift-Option-Command-R).

If neither of these things work make sure you are on a regular (non-cellular) home-residential Internet connection (i.e. not public, not cellular-based, not a business or school where they likely have a proxy server) and restart your router/modem and try again.

If you don't want to take it piecemeal you can do all these things at once as well, and try again that way.

This is how you do the NVRAM reset:

https://support.apple.com/en-us/HT204063

(you simply boot up with Option-Command-P-R, and then turn it off again, and try the Shift-IR below)

If you can't figure it out though, simply do the Shift-Option-Command-R boot as that will probably work regardless. The NVRAM is just one of the three things that could (alone) help.

Did you specifically do Shift-Option-Command-R?

If your Mac is old enough to have an Ethernet port you should try using that plugged directly in the router.

I assume you have also attempted to restart your modem and router, and that your service provider is cable/dsl/or fiber. Otherwise, your internet may not be fully unblocked of all ports and you should try at a friend's house.

If your router is set to 5Ghz-only, you can also try setting it to 2.4Ghz only in the router setup.

You can also get the Genius Bar to do this for you for free with an appointment.