Working on building a portfolio, I returned to an earlier experience project and noticed that all of the attached maps failed to load. I decided to remove the data links and add them back in the hopes that the problem would be resolved. But attempting to add any data back via the "data source" pane results in an error: "Item does not exist or is inaccessible". In fact, I can't add any of the several dozen items from my content library, nor from any other library to which I have access. I tried to do so in a brand new experience and received the same error.
It appears as though all of the public experience gallery projects also have broken links at the moment. Is this a global issue?
Update: This appears to only be an issue in Firefox. I loaded the same content in Chrome with no errors and was able to reconnect my data sources.
I tried clearing my browser cache in Firefox, but I am still unable to view any Experience data content in the browser.