NS records not fully propagating on subdomain

[dsjwww]

What is the name of the domain?

register.vaillax.com

What is the issue you’re encountering

NS records not fully propagaing after 48 hours for subdomain

What steps have you taken to resolve the issue?

I have added four NS records from a 3rd party vendor crossbar
ns1.crossbar.org, ns2.crossbar.org, ns3.crossbar.org, ns4.crossbar.org
(for register.vaillax.com)

According to Crossbar, they are set up correctly.

I must be missing something because they don’t want to propagate in the US.
Any assistance would be greatly appreciated!

What are the steps to reproduce the issue?

see https://dnschecker.org/#NS/register.vaillax.com

[sjr]

The delegation is in place and working from the Cloudflare DNS, but the crossbar.org nameservers are not returning any records (NS or other) for your domain…
https://cf.sjr.dev/tools/check?84260052999e4a7885fc32df40dac74c#dns

dig +trace +nodnssec register.vaillax.com ns

; <<>> DiG 9.10.6 <<>> +trace +nodnssec register.vaillax.com ns
;; global options: +cmd
.			514672	IN	NS	a.root-servers.net.
...
.			514672	IN	NS	m.root-servers.net.
;; Received 239 bytes from 127.0.2.2#53(127.0.2.2) in 186 ms

com.			172800	IN	NS	e.gtld-servers.net.
...
com.			172800	IN	NS	m.gtld-servers.net.
;; Received 845 bytes from 192.203.230.10#53(e.root-servers.net) in 18 ms

vaillax.com.		172800	IN	NS	zainab.ns.cloudflare.com.
vaillax.com.		172800	IN	NS	kayden.ns.cloudflare.com.
;; Received 369 bytes from 2001:500:d937::30#53(l.gtld-servers.net) in 172 ms

register.vaillax.com.	300	IN	NS	ns1.crossbar.org.
register.vaillax.com.	300	IN	NS	ns2.crossbar.org.
register.vaillax.com.	300	IN	NS	ns3.crossbar.org.
register.vaillax.com.	300	IN	NS	ns4.crossbar.org.
;; Received 133 bytes from 172.64.34.149#53(zainab.ns.cloudflare.com) in 21 ms

;; Received 38 bytes from 2600:9000:5300:ee00::1#53(ns4.crossbar.org) in 38 ms

[dsjwww]

Thank you. I have sent your message to crossbar. I appreciate your quick response!!