Infinate wood in sack not working

I have just bought the woodman class and I cannot get my sack to store the extra wood. I have restarted the game 4 times. It has been leveled up to level 2 and 3 each time and I have tried with the brown sack and the good sack. Not sure what else to do. 😩. Has anyone else had this problem? Any suggestions would be gratefully received.