CRM 2015 Marketing List crash - partial "reinstall" / download

Been in and out of marketing list as we are setting up a campaign. Now since a few hours back I just get error message heading into the menuitem Marketing / Marketing lists in regular CRM Online 2015. Tried IE and Chrome browsers as well as closing all and starting over, no difference. Could only find one other person / entry with same problem, but no documented resolution. ANyone encountered the same, and possibly have a solution? Is it possible somehow to just re-load / reinstall / download just portion of CRM Online, ie just the marketing list part that seems to have gone bust? Is it possible to just "upload" from the sandbox environment?