How to set up electron with 3rd party sim?

Hi,

This is my first particle board. Unfortunately the particle sim does not work in my country (during setup it never reached the breathing blinking behavior). I placed a 3rd party sim and finally figured I could enter the 3rd party sim code where it asks for the particle sim code.
Then it asks me to enter the APN and download the firmware, but there is where I’m getting stuck now. When I try to download the firmware it tells me to check my internet connection, because it cannot download from Particle servers. However, when I look at the download request I’m getting the following error: Build target is not supported anymore.
And obviously I have internet connection.

I also tried from the CLI, but I got a message there saying I have to do continue using setup.particle.io.

So, I’m stuck and can’t figure what to do next. I read that it may not necessary to flash the firmware as you can just insert two lines of code when you add a program, but in my case the board is not even linked to my account yet.