ok, i saw the user line in my dsl-provider-config.
it was just a few lines down at the end.

now i took a look at /etc/ppp/pap-secrets and there is the matching user name and password.



aha, but now i found a error in chap-secrets.

there is a not finished username in the first row.
i delete that now, save it, reboot Linux and then i see whats the deal...