If your Portfolio page appears like the following, your default domain might be incorrect:
In order for a default Portfolio to appear active, the domain must match your current username:
You can correct this by going to the Domain section of your Portfolio Editor.
Don't forget to Save and Publish when you're done!
Another cause could be that your Portfolio's theme is being updated:
In this case, try switching your theme in order for your Portfolio to appear active in the meantime! Again, don't forget to Save and Publish when you're done.