In case when Avaya SIP phone can make calls using short numbers (e.g. 400) but cannot make calls to external numbers
- Enter Extentsion-> phone password - set password with 8 or more symbols
User->Telephony->Supervisor Settings->Login Code - enter same as step 1 and uncheck Force Login
Using web page of device: check Settings->SIP->password - should be the same as in IP Manager for this device and extension