Hello,
after FAS to Accounts switch I was not able to kinit. It would be probably worth documenting this error message in some FAQ for the FAS->Accounts migration - especially when using the 2FA(OTP).

I have:
1) reset the password in https://accounts.fedoraproject.org/
2) add the second factor OTP - https://docs.fedoraproject.org/az/fedora-accounts/user/#twofactor
3) test the changed password works for the website (https://accounts.fedoraproject.org/, https://src.fedoraproject.org/dashboard/projects)
4) follow the guide on how to initiate the kerberos ticket - https://docs.fedoraproject.org/az/fedora-accounts/user/#pkinit

When trying to initiate the armor.ccache it was asking for a password and none of the passwords worked (fas/accounts/accounts+otp) getting following message:
$ kinit -n @FEDORAPROJECT.ORG -c FILE:armor.ccache
Password for WELLKNOWN/ANONYMOUS@FEDORAPROJECT.ORG:

Upgrading+reinstaling the related packages fixed my problem (probably just upgrade is fine).
dnf -y update fedora-packager krb5-pkinit

I believe that it would be worth mentioning in the guide (https://docs.fedoraproject.org/az/fedora-accounts/user/#pkinit) that krb5-pkinit package is needed and that it is installed as dependency by the latest version of fedora-packager and it was not there before, so it is actually it is actually "update/install fedora-packager" instead of "install" in the guideline https://docs.fedoraproject.org/az/fedora-accounts/user/#_1_install_fedora_packager

Also I would recommend to explicitly mentions that the "kinit -n @FEDORAPROJECT.ORG -c FILE:armor.ccache" is not supposed to be asking for any password.

Best regards
Michal Ambroz