DNS lost SITE time to time

Hi fellows
have a pretty new site (2 weeks only)
I have faced a interesting issue
my site time to time -1 time per week totally lost from 1.1.1.1 DNS

but on other DNS providers (GOOGLE, OpenDNS etc ) it works good

I see one of your nameservers looks broken:

https://dnssec-analyzer.verisignlabs.com/gixo.co.uk

ns5.be-dns.net returns REFUSED for gixo.co.uk/A
ns4.be-dns.net is authoritative for gixo.co.uk

Oh
i see where is the problem
thanks