Not leveling properly//or at all

Hi there! I tried to read the documentation and ask the instant support bot (gave me a error), also used the config commands So, the bot is either not leveling people, or doing so at a very slow pace. For example someone joined the server and had sent around 200 messages, however when i used /rank lurkr said they had no XP. I used the level calculator on the site and it said reaching level 4 should have taken 13 messages. (I bumped up the multiplier because it was extremely slow) Older members are gaining xp, I also saw someone gain 4 levels within a hour or so., so it seems as if it works sometimes. Any help is appriciated, ty! Pictures below;