half of Command block does not work

i was doing a map with a friend (so we use a lot of command block) and i don't know why it's doing this but the lastest command block that i place don't work its on [Repeat] [Unconditional] [Always active] and it's does not say that the command has failed it set nothing so in first checked if the command block are actived (it's active but still doesn't work) i set the server on the vanilla to see if it's a plugin who do this problem (it change nothing) and i checked the ram of the server it's not empty or very low [1700 mb] if there a solution ? or is the server that doing bad ?