When I try to acess developer.apple.com, I receive 403 Forbidden Apple and nothing more.
developer.apple.com is down
I have same problem already few days
I'm also getting this on Firefox and Chrome, but unsurprising it works fine on Safari... Just Apple doing Apple things.
But anyways, go into your browsers Inspector, click on storage, and delete all cookies associated with https://developer.apple.com/
That worked for me.