Seems like only one of Kenic name servers is answering queries, the rest seems to have an issue, likely the reason .ke domains are having issues.
dig zuku.co.ke ns @b.ns.kenic.or.ke.
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.3 <<>> zuku.co.ke ns @b.ns.kenic.or.ke.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43884
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;zuku.co.ke. IN NS
;; AUTHORITY SECTION:
;; Query time: 27 msec
;; SERVER: 213.147.83.19#53(213.147.83.19)
;; WHEN: Fri Dec 16 07:22:28 2016
;; MSG SIZE rcvd: 78
dig zuku.co.ke ns @ole.kenic.or.ke.
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.3 <<>> zuku.co.ke ns @ole.kenic.or.ke.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 38282
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;zuku.co.ke. IN NS
;; Query time: 17 msec
;; SERVER: 198.32.67.19#53(198.32.67.19)
;; WHEN: Fri Dec 16 07:22:51 2016
;; MSG SIZE rcvd: 28
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.3 <<>> zuku.co.ke ns @
ns1.afrinic.net;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 15479
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;zuku.co.ke. IN NS
;; Query time: 54 msec
;; SERVER: 196.216.2.1#53(196.216.2.1)
;; WHEN: Fri Dec 16 07:23:07 2016
;; MSG SIZE rcvd: 28