if one of my mods/RDAs "misbehave", first thing I do is break everything down and give it a good cleaning, put it back together and recoil/rewick.
I don't own a limitless, but aren't they a direct battery connection? make sure the center pin of the atty is sticking down far enough to make the connection. If your still having problems, try the atty on a different mod and a different atty on the MOD. that will help determine where the issue is.
oh, and make sure your battery is charged.
