If you are moving your site to Heberdomaine or there has been some other change to your website's DNS records, the most likely cause is that your ISP or PC itself, have failed to reflect the change and have a cached or stored record. DNS is quite a complex system, but in short this means your PC or your ISP's DNS server has the record prior to the change and it needs to be updated to reflect the new DNS records.
In most cases, this will be caused by your PC and can be resolved by following the below steps. Be sure to follow in the same order, as this is important when ensuring the correct updates are obtained.
The above steps will prompt your PC to obtain the new DNS records from your ISP.
In the odd case, the ISP may also have stale or cached records. In this case, you will need to be patient and wait an hour or two for the records to update.