Yes, the reason why they don't work is the chunks don't load anymore because minecraft doesn't see those chunks as useful because there is no player nearby.
So you have to make them in the spawn chunks, since the spawn chunks are always loaded. Unforunetly it seems as if your command blocks are not near spawn so you have to use /setworldspawn above your command blcoks, If you don't want the players to be near the command blocks due to lag you can put the following on a clock in the center of your command blocks
/tp @a[m=<default_gamemode>,r=500] The current spawn in x y z
default_gamemode should be entered as 0:survival 1:creative 2:adventure 3:spectator
That will teleport all players that enter the world for the first time (since they will be in the default gamemode and in a 500 block radius of the command blocks since that is where the world spawn is located) will be teleported to where you want the players to actually be the first time.