Can't add button on soft keys give error

[iamjohn22]

On a IP 4620 station number 811 called test template. I did a list usage and there was no data. I statused it and it was out-of-service. I did a remove station 811 command and when I hit enter, the screen appeared with the red text like I was doing a change station, and the cursor was flashing next to the TIMER button, with the meesage as inidated belowÂ….the button type isn't allowed, but it was already programmed on the phone? I tried to add feature button again on this 4620 station and says button type not allowed. How was it allowed before? Any clues! Thanks
John