You can only operate a WordPress database under one domain name. The domain name is stored in WordPress.
When you change the domain name, there are two places in the WordPress database that need to be changed.
Select your WordPress database
Select the options table
In the option_value column, look for the values called site_url and home. You must change the option_name column associated with each of these to reflect your new domain name.
If you are using the upload feature, you may need to select a new upload path because your server path probably changed with the new domain name.
That should fix it.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin