There is a major eBay server issue affecting many,  you are not alone.

eBay are aware,  and working on this,  but it is intermittent,  so perhaps try a little later on today,  or even tomorrow if you are trying to list more items.

However,  if it's the app that you're using, some peeps have found uninstalling and reinstalling the app , the account is then accessible.

Your lovely BMW is clearly showing for sale, it's on at £8,000 with 14 bids currently.

@e.j.a.z