Number Range for Material Type

Hi Expert,

I got this error message during Material Creation (MM01).

No external number assignment possible for mat. type Axs Raw Materials

Message no. M3317

These are what I have done

Configuration:

1. SPRO-IMG-"Logistic-General"-Material Master-Basic Settings-Material Types-define attributes of material types
2. Create Axs Raw Materials
3. Untick External no. assignment w/o check. 
4. Save

1. SPRO-IMG-"Logistic-General"-Material Master-Basic Settings-Material Types-Define number ranges for each Material Type
2. Create new Group named ABC Raw Material
3. Add number range from no:000000000001000000 to ZZZZZZZZZZZZZZZZZZ and tick external tick box
4. Assign Axs Raw Material to element group ABC Raw Material
5. save

Creating Material

1. MM01
2. Material = 1102017
3. Industry sector = Axs Pte Ltd
4. Material Type = Axs Raw Materials
5. Enter
6. Then I got error message : No external number assignment possible for mat. type Axs Raw Materials

Please advise which configuration I missed

Thanks in advance

Regards,

Kenzo