Others have been receiving this rather odd message.

There is a major eBay server issue affecting many.

eBay are aware,  and working on this,  but it is intermittent,  tis may be impacting your account,  and sending this odd message.

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

@cad1720