1. It is quite confusing to have website’s domain name as www.guitarcollection.com.my and at the same time the email domain as guitar-collection.com.my, with the ‘-’ in it. It has always been a good practice to have one single domain for both web and email services.
2. Both DNS servers for guitar-collection.com.my are probably at the same physical location or data centre. In the event where the data centre is down, there is no redundancy support for DNS service.
3. One of the DNS server does not respond. This will worsen the situation because there will only be one DNS server working.
4. Apparently, the web and email servers are located in the same server. Due to the complexity of emails today (Spam control, webmail access, virus filtering, etc), it is not ideal to setup both services using just one single server. Obviously, this also shows that the server is without load-balancing or dedundancy support. Afterall, there is only one Mail Exchange (MX) record found!
P/S. Both guitar-collection.com.my and guitarcollection.com.my are pointing to a same website. They should have decided on one of the domain as the official domain, and direct the other to it using Redirect 301 method to accumulate PageRank values.