If dns was just changed on the site. What you are seeing is normal for the first 48 hours.

When DNS changes are made it takes 24-48 hours for those changes to propogate throughout the Internet. Even when (from your connection) it looks like the change has propogated, the next time you connect to the site it may appear the the change has reverted back to the old server or perhaps the registrar's placeholder page (on newly registered domains). This is due to the fact that your connection settings let your ISP assign the DNS server upon connection to the Internet and you may be using a DNS server that has not yet been updated. Even though minutes before you were using a DNS server that WAS updated. Give it another half day (or full day) and everything should settle down and there will be no more problems.