Clojurians Log v2

Hi. I am struggling to deploy my app to Tomcat. On the first attempt lein uberwar failed in lein 2.9.1, but I got around that by downgrading to 2.8.3. Now when uploading the file to tomcat/webapps I get the error clojure.lang.ArityException: Wrong number of args (1) passed to: iso-ukhozi-app.handler/app, what is tomcat trying to pass to the app? And how do I fix this? Thanks.