Could you please send us the screenshot of the error that you are getting while trying to add the portfolio item? To add the portfolio, you can go to your profile and scroll down until you see a 'Portfolio' section. Click on the '+' icon and follow the steps on the page.
I`m not sure why but I`m also not able to view the screenshot, could you share the text of the error you`re receiving?
I would also suggest clearing your cache and cookies or logging in with another browser to add your portfolio. Thank you.