That might be some issue with your workstation / connection, that for some reason can't connect to Steem API nodes (just guessing now), could you check if going to https://api.steemit.com/ gives you response like:

{"status":"OK","datetime":"2019-12-20T09:14:41.772867","source_commit":"ae6c6c77601436e496a8816ece2cbc6e26fbe3c2","docker_tag":"latest","jussi_num":39198399}

?