Hosted Zone ID: Z09356803PV7JJHFT8DEP

Run this command in the Account where Private Hosted Zone is Created.

aws route53 create-vpc-association-authorization --hosted-zone-id Z09356803PV7JJHFT8DEP --vpc VPCRegion=ap-south-1,VPCId=vpc-0e524fb7ec2651a65 --region us-east-1

External AWS Account:

aws route53 associate-vpc-with-hosted-zone --hosted-zone-id Z09356803PV7JJHFT8DEP --vpc VPCRegion=ap-south-1,VPCId=vpc-0e524fb7ec2651a65 --region us-east-1