Depreciation key TST1 not allowed (Check your entry)

Dear Gurus,

I am creating a new asset, while giving the dep. key in the dep. areas, i am getting this error message.

My dep key is showing in the list.

Depreciation key TST1 not allowed (Check your entry)

Message no. AA119

Diagnosis

Depreciation key TST1 is not defined.

System Response

Processing is terminated.

Procedure

You have the following choices:

Use a defined depreciation key (use input help).

Define a depreciation key in Customizing ("change" pushbutton) and activate the key.

regards