Button Mapping on NBX 100

[thekriskokid]

We just took over maintenance on an NBX100 and I am trying to make some simple button mapping changes. Whenever I try to "Apply" my changes, I get this error: "Unable to save changes. No device exists with the specified extension!" Can anyone give me assistance? I've worked on these some years ago, but it's been so long, I'm sure I'm missing something simple. thanks.
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[donbru01]

Hi verify into TelephoneGroup if button are locked .

 

[thekriskokid]

Thanks, I figured it out.