Not Receice Calls (486 Busy)


I have DP750-720 (FW on Issabel PBX (asterisk 13)
It does normally Register
External calls works fine

Μy problem is that i can’t get incoming calls

Called SIP/103
– Connected line update to SIP/105-0000000a prevented.
– Got SIP response 486 “Busy Here” back from
– SIP/103-0000000b is busy
== Everyone is busy/congested at this time


Sounds like DND is on


Bug, another fix in beta, maybe this time it will work.


Solved with hard reset DP720
Disappear DND icon
Before reset icon it was stuck



There is a setting under handset LCD -> Preferences -> Mute as DND. After you configure it to “Enabled”, you will be able to use the “Mute” button to turn DND on and off. I guess this setting was set to Disabled after you accidentally enabled the DND, so you cannot turn if off again. I will suggest our SW team to just turn off the DND when the Mute as DND option is disabled.