When you activate a domain to be mapped to your blog at Account > Domain Mapping and there is no design displayed on your blog, this happens when the stylesheet, which contains the design elements for your blog, is not found because your domain isn't ready to be set as active.
Or the domain may not have been set up correctly. In order for domain mapping to work properly, you will need to configure a CNAME Record at your registrar. Services such as domain forwarding or domain masking (sometimes called URL Frame) are not compatible with Typepad's Domain Mapping feature and may cause your blog to display incorrectly. Information on the differences between mapping, masking, and forwarding a domain is available in the Domain Mapping FAQ.
How do I fix it?
Go to Account > Domain Mapping and click to Deactivate the domain to restore your blog's design.
If it has been more than 24-48 hours, then the domain mapping may not have been set up correctly. Check your settings at your registrar and make sure that you are using the correct CNAME Record and not domain masking.
See the Domain Mapping article for more information.
If you continue to encounter a problem or would like help setting up Domain Mapping, contact Typepad support at Help > New Ticket.