Directed call pickup on Yealink T48G is not working


on our T48G phones the directed call pickup isn’t working.
When the BLF is blinking red on the other extension, it looks like pressing the button generates only ** , and the other extension is not picked up.
Dialing the **2## manually works fine.

The phones are provisioned like this:

features.pickup.direct_pickup_enable = 1
features.pickup.direct_pickup_code = **
account.1.direct_pickup_code = **
linekey.1.line = 1
linekey.1.value = 230
linekey.1.pickup_value = **
linekey.1.type = 16
linekey.1.label = Displayname

Can anyone help me out?
The phones are on firmware:


I’m having the same issue with a T46S, were you able to find a solution?

Log into the phone and look at DSSKey -> Memory Key page.
You should see:
Type: BLF
Value: (extension number being monitored)
Line: Line 1
Extension: **

Also, on Features -> Call Pickup:
Directed Call Pickup: Enabled
Directed Call Pickup Code: **