If you are using older version of eSteem, you are likely connecting to steemd.steemit.com server by default and app is not able to fetch posts because server is announced and discontinued/upgraded to https://api.steemit.com. So please update you connection node to one of public end-points/servers.
Go to Settings page and change Server field to one of the servers listed below and save changes (sometimes restart of app might be required). It should start working again...
Thank you 