At least some users seem to be having good results holding down the shift key and refreshing the active listings page (a hard refresh), which would seem to indicate a cache issue, possibly due to a change on eBay's end conflicting with local cached data for those users.
If it is a cache issue, clearing the cache ("for all time" if that option is available) should solve the immediate problem. Otherwise, manually erasing just the eBay cookies and restarting the browser or device may help.
Using an alternative link may also serve as a temporary workaround.
https://www.ebay.com/sh/lst/active
https://www.ebay.com/mys/active
