- Power up the ATA
- Make sure the ATA is *NOT* plugged into the network.
- Plug an analogue phone into voice port one.
- Lift the handset, and press the button on top of the ATA
- You will be greeted by the American female darlek.
- Dial 322873738#*
Open ADSI Edit
Navigate to User
Right-click on Properties
Navigate to proxyAddresses or if Exchange Schema is loaded msExchShadowProxy
Add or correct -> SMTP: <email address is added>
Apply the changes and force a DirSync to Office365 Azure AD
See the article: