Why does my fit bit lose track of my steps

My Fitbit is not accurately counting steps. It starts out great and ten somewhere around mid-morning in starts all over again with the step count

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0