We got a new .io domain name from NIC.io and later realized that NIC.io is just a domain registrar and they do not provide DNS.
DNS is required for adding A records (the domain name to IP address mapping) and CNAME records (Canonical Name or aliases – say http://www.example.io is an alias to example.io). So I ended up using Amazon Route53 for the DNS. Added the A record and CNAME and the URL started working in about 15mins. Next we wanted to setup emails like email@example.com and created a Google Account. Google first verifies the domain – For this I had to add a TXT record in Route53. Next Google wanted to verify mail setup and asked me to add MX record with name “@” and 5 Google NS entries. Added the same in Route53 console but got error that my DNS is not reachable.
The trick that fixed the issue is not entering “@” for name in the Route53 MX record. Just leave it blank if you see this issue and the mail setup will work.