nameserver issue after migration

Recently I have transferred all of my Cpanel accounts to another server by "Transfer or Restore a cPanel Account" (Remote User Account Transfer) Using my previous server IP address and user pass. Note: Previous reseller account user was "example1" . and currently I have created the same user name with the same domain on the new server as a reseller account. and all Cpanel accounts transferred under this reseller account. ( i don't want to force my customer to change nameserver, i wanted that they will use the previous nameserver with my new server) I have transferred successfully. but now I am facing a problem with nameserver. my previous nameserver was "ns1.example1.com", "ns2.example1.com" . with IP address "23.88.x.xxx" (server IP) my nameserver's domain registry is porkbun. and my current server IP is "195.3.xxx.xxx". I have updated the glue record and DNS zone with my new IP address on porkbun . also updated DNS zone record, ns record with the name IP address on whm. Almost 24 hours passed. but at https://intodns.com/static/images/info.gif
Domain NS records Nameserver records returned by the parent servers are: blerghjbwmwadujyi.hydrapiglephant.com. ['23.88.x.xxx'> [TTL=172800] blerghmurrzelbjbb.hydrapiglephant.com. ['23.88.x.xxx'> [TTL=172800] c.gtld-servers.net was kind enough to give us that information.

NS

alt="Info">https://intodns.com/static/images/info.gif

NS records from your nameservers

NS records got from your nameservers listed at the parent NS are: ns2.example1.com ['23.88.x.xxx'> [TTL=86400] ns1.example1.com ['23.88.x.xxx'> [TTL=86400]

and gettings this error.

alt="Error">https://intodns.com/static/images/error.gif	Missing nameservers reported by parent	FAIL: The following nameservers are listed at your nameservers as nameservers for your domain, but are not listed at the parent nameservers (see RFC2181 5.4.1). You need to make sure that these nameservers are working.If they are not working ok, you may have problems! ns2.example1.com ns1.example1.com
alt="Error">https://intodns.com/static/images/error.gif	Missing nameservers reported by your nameservers	ERROR: One or more of the nameservers listed at the parent servers are not listed as NS records at your nameservers. The problem NS records are: blerghjbwmwadujyi.hydrapiglephant.com blerghmurrzelbjbb.hydrapiglephant.com This is listed as an ERROR because there are some cases where nasty problems can occur (if the TTLs vary from the NS records at the root servers and the NS records point to your own domain, for example).

how can I solve this issue? almost 24 hours gone. still same. I have updated the server IP at the DNS zone, and glue records. but still same error. Note: I have not removed anything from the previous server yet. what should i do now? how can I fix this error?