How to deal with "Your Apple ID currently has two-step verification turned on, but two-factor authentication is required." on developer.apple.com?
Two-step authentication is an older method of authentication for your Apple-ID. This is no longer "good enough" to be used with developer accounts.

You MUST upgrade to two-factor authentication as a developer. There's no way to login as a develop with two-step authentication anymore.

Apple has a detailed guide on enabling two-factor authentication here:

https://support.apple.com/en-us/HT204915

Basically you take your iOS device, open Settings and click your name at the top. Choose "Password &amp; Security" and then tap "Turn On Two-Factor Authentication". You'll then be guided through how to verify your phone number.

If you want to do the same from a Mac, you have to open System Preferences and click "Apple ID". Choose "Password &amp; Security" from the menu on the left and then click the "Turn On..." button alongside "Two-Factor Authentication".