Cisco phones and unreliable BLF field

I have 20 Cisco SPA504G phones with Attendant consoles.
I set up BLFs for all of them.

After a long struggle, i've got them to work.
But they are unresponsive and unreliable.

When an incoming call to all phones is placed, all phones ring but the flashing red lights are random, very few times they all flash, most of the times only half of them flash.
This is for all sorts of calls. How can we improve the reliability of the BLF?

Here is a screenshot of our config:
http://d.pr/i/eklA

RE: Cisco phones and unreliable BLF field

I have the same problem setting up BLF our Cisco 8851 and I would like to have an answer if PBXes supports it and how to configure it.

RE: Cisco phones and unreliable BLF field

Was anyone able to get this resolved? I have clients with CISCO SPA504 and SPA508. The BLF will work if internal extensions are called. They turn on while an outside line is called but after it is answered the extension looks available again even though they are talking to an outside call.

Also, I cannot get intercom to work at all.

This post has been edited 1 time(s), it was last edited by qii on 10.07.2019 at 01:23.