I’m running Jetpack Version 4.1.1. Permalink did not help.
I’ve not been able to replicate on my own test site using the latest version of Jetpack (4.1.1) and Espied. This leads me to suspect that there is a conflict between one of the other plugins on your site.
Can you please try disabling all of your plugins with the exception of Jetpack and then navigate to Settings > Permalinks to re-save your permalink structure again?
If the page still leads to a 404 error, please search for any pages, posts, tag, category or other content on your site that may be named “portfolio.” If you find one, rename it and then try re-saving your permalink structure again. A shared slug could be the cause of the problem.
As a last suggestion: Try switching to one of the default themes, deleting Espied from your site, and then re-installing/re-activating the theme.
We can continue troubleshooting if those steps don’t help out.