Please check your connectivity or change the API server in the settings to another one
o,sorry,20160328witness_node unable to sync up
Is this a new build of the witness_node or one that was previously synced to the network?
If previously synced, you may add --replay-blockchain to the command line sting. Further, if the database became corrupt, you may add --resync-blockchain and this will download from peers starting at block 0.