Outgoing call won't show extension number

[agl_w73p]

Hello,

I am new and enthusiastic user of Yealink W73P DECT phones.
I sum up my problem as follow:

Set-Up: W73B Base with 8x W73H Handset. Central number with extension -0 and all the handsets with extensions number starting from -10 up to -17. Incoming call goes to all extensions number. Each extensions number is set as individual account in W73B base station.

Problem: outgoing call shown from each handset shown as central number (-0) instead its own extension number.

Question: How can I solve this and where to look?

Thank you in advance and looking forward to hearing from you.

Best,