Not an apex domain
The domain 248.29.3.213.static.wline.lns.sme.cust.swisscom.ch is not the root of its zone.
Instead, try zone transfer on 29.3.213.static.wline.lns.sme.cust.swisscom.ch .
Instead, try zone transfer on 29.3.213.static.wline.lns.sme.cust.swisscom.ch .