As per the most from j.schulenberg, 'CTL update failed' means the phone could not get the CTL file.
Now, let me ask you this, is you CUCM cluster in secure/mixed mode?
You can verify that by going to Enterprise Paramters page and look for 'Cluster Security Mode' if its anything but 0 than your cluster is in secure(2) or mixed(1) mode.
Now, do you want your cluster to be in secure/mixed mode or not? If not, that you need to change the cluster security mode to unsecure(0) using the CTL client. If you want it to be in secure mode, you need to make sure that the TFTP server that the above mentioned phone connects to is in the list of servers in the CTL client.
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The short answer is that you don't.... That isn't entirely true while at
the same time it kind of is, but for the most part you don't configure
the softkeys. You enable or disable them via TCL. Here is the long
answer. Be sure to read the whole thing or e...
Topology: IP Phone > Switches > Microsoft NPS setup to forward 802.1x
proxy to > ISE 2.1 patch 3 Authentication: EAP-TLS using Cisco MIC SANs
Phone Models 802.1X support? 802.1x flavor Addtl Comment EAP-MD5 EAP-TLS
Cisco 3905 Y Y N Cisco 6911 Y Y N Cisco ...