Fritz! Box 7170 wants not to announce itself/cannot

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Hello,

have since short the problem that itself my Fritz! Box hair dryer WLAN 7170 no more with web.de to announce can/wants. Since me the “web.de Fritzen” copies in each case assistance texts into its Antwortmails, are now you my last hope:

In the system log those announces to Fritz! Box “registration of the Internet call number 012123xxx was not successful. Receiving station announces a cause 401 ".
Have under “Internettelefonie” the following attitudes:

Internet telephone IE offerer: “other offerer”
Internet call number: “012123xxx”
User name: [Web.de address without “@web.de”]
Password: 100%ig correctly
Registrar: “sip.web.de”
Pro XY server: “sip.web.de”

The amusing to the fact is still that it funkioniert perfectly over the PC with the FreePhone software - with above users/password combination (on typing errors examines several times).

Have you ideas?

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Have after I still another bischen rumkonfiguriert the problem found:
The option “Internet call number for the registration do not use” may be activated! When exact thinking machts also, but perhaps habens already different ignore sense