GXP2170 BLF shows status unknown/offline


Hey Guys,

First of all, I am not an IT-genius. I try to find the problem I am facing at the moment in diffrent forums. It took some time to find a post, which is relating to my problem Presence Watching on Asterisk / FreePBX?

I am facing nearly same problems. We are using gxp2170 on freePBX. We use BLF to show: 1. if some extension is busy especially to see if our second ringgroup is available for an active call; 2. to make an internal speed dial. For 1 or 2 years it worked, just with small problems like BLF greyed out (status = offline/unknown) on all devices. This issues normaly could be solved by rebooting them, or make an update of FreePBX if it was available.

Used firmware was image

Because this status wasn´t satisfying and to fix some other issues I made an update on one device to prog. After update phone and BLFs were working well for 1 week.

Till now we didn´t used freePBX IP in BLF-Server field, but it worked before.

Now BLFs are greyed out on all extensions since several days.
What I did till now:

  • reboot of all devices, several times.
  • reboot freePBX-server (VM) on our server
  • reset VPK /BLF on two devices
  • fill BLF-Server field on two devices
  • make firmware update on second device

Maybe firmware update have to be done on all devices, but I hardly belief that out of two reasons: 1.It worked for 1 week. 2. I discovered that one device was on a diffrent firmware all the time.

Is it me who did one or many mistakes, or is it GXP2170, FreePBX or connection of both which don´t work well?

If some Information is missing, just let me know and I try to provide it. Thank you guys in advance.

Best regards,


1st go back and read the firmware release notes for all the various versions between the old and new and see if you can identify any settings that may have come into play as a result.

Check to see if the update was done correctly as you (seemingly) made a fairly big jump and oftentimes there is a prescribed sequence of upgrades that should be followed.

Check FPBX to see if it is updated as well and if not, consider doing so.

Get into the phone web interface and check that the settings are correct for the PBX.



I’m wondering if you ever got this resolved, we are seeing something similar on a 3CX deployment, where the BLFs will all disconect\reconnect.



It would help to know firmware version and other info related to 3CX as there can be many causes.

The most common cause is when a phone fails to respond to a Notify or the PBX fails to see the response. When this occurs, the PBX will remove the subscription and discontinue sending messages to what it thinks is an off-line phone. At that point either the subscription has to be renewed or the phone rebooted, which cause the renew. This is typically related to a network issue or congestion of some type.



Thanks for the information on the a missed Notify being the issue, we will do some packet captures to see if we can see this failing.

The phones are currently on, 3CX is 16.0 Update 2 hosted on Lightsail, with a local Linux SBC as the Windows SBC seemed to keep needed a service restart.



Good luck, won’t be that easy. You might also get into 3CX and set the notification if an extension changes registrations.