Ladders on Servers

I was on a LAN world with my sis, and we were building an automatic ladder. It was powered by a series of commnd blocks with this command:

/setblock ~ ~ ~ minecraft:ladder

It worked, kind of. When it spawned, the ladder stood for a second, but then broke into items. We were confused, but when I did some testing in a singleplayer world, the command worked just fine! So what gives? Is there a special command we need to be using in servers? Is it a lag problem, or what?

Solution 1:

I.... uh... actually realized there was a specification issue. When we tested in the singleplayer world, it was facing north. when we tested it in LAN, it was supposed to be facing east. We got our numbers wrong.... Boy do I feel stupid...

Solution 2:

As Fabian said, singleplayer is like your own server. When more than one person is loading in chunks in a server, it reload blocks. As the ladder is seen by the code not having a block, it breaks the ladder. Try a chain command that has a fill replacing air water and lava behind it to a barrier.