So I have plenty of slots available in my chassis, and I have plenty of DKSC16+ cards to install...but I am getting the following message when I try to add another keyset:

[Linked Image from i.imgur.com]

I am not getting any useful results on the error from Google. Is this some kind of licensing limitation? If so, is it even possible to purchase more of these licenses now?

Can I remove some of these non-dial "keysets" shown below? (100X numbers are not actually extensions - they were setup by previous employees - unsure what they do)

[Linked Image from i.imgur.com]

Or does anyone have a way I can continue creating extensions on this system? About information:

[Linked Image from i.imgur.com]