A few options: Device > Phone and in the "Phone Load Name" type the phone firmware name like "SCCP11.8-5-2S" (try to find the correct Phone firmware name). Then save + reset. If this doesn't work, try a factory reset of the 7911: Step 1 Unplug the power cable from the phone and then plug it back in. The phone begins its power up cycle. Step 2 While the phone is powering up, and before the Applications Menu button flashes on and off, press and hold #. Continue to hold # until the message LED on the handset flashes on and off in sequence in red. Step 3 Release # and press 123456789*0#. You can press a key twice in a row, but if you press the keys out of sequence, the factory reset will not take place. After  you press these keys, the message LED on the handset flashes faster in  red and the phone goes through the factory reset process. Do not power down the phone until it completes the factory reset process and the main screen appears. ... View more

Indeed, you have 2 flavors:      BLF Speed Dial      and/or      Presence in the directories (Missed calls, received calls, ...) In your case (extension mobility), you should configure each end user with:      Presence Group = Standard Presence Group      Subscribe Calling Search Space = Select a CSS which allows to view all internal Directory Numbers You should also configure the Directory Number of each Device Profile to be part of the Standard Presence Group. ... View more