FWA710 Static DHCP not added

Trying to add a static DHCP on LAN group without success.

IP-settings:

'Default' group(WIFI cfg): router ip : 192.168.0.1 ; range 192.168.0.10 - …254

'LAN' (Bridge1) group : router ip : 192.168.1.1 ; range 192.168.1.10 - …254

Going to 'Static DHCP' -page.

Selecting 'LAN'-group and manually inserting Asus main router's WAN-port MAC-address (as seen under clients/wired) and setting wanted IP to 192.168.1.100.

Clicking 'OK' and back to list - no entry.

If I instead of manual pick the Asus in the droplist it is the same.

It is in the picklist both when group is 'LAN' and 'Default' (where iPad connected).

What am I doing wrong?

Best regards

Jan