How can I run a Luminus project which uses Overtone?

Question

I'm writing a web app which uses Overtone. When I try running the app using lein run or when I try to start the repl while in the project's directory I get the same error: java.lang.ExceptionInInitializerError at clojure.main.<clinit>(main.java:20) Caused by: java.lang.Exception: Server needs to be connected before you can perform this action.

It seems to me that both of those actions make all the files in my project compile. Is there any way to compile the namespaces which use Overtone after I run the server? Or maybe this isn't the issue, and the problem is coming from something else?

Here is my project.clj file:

(defproject comusic "0.1.0-SNAPSHOT"

  :description "FIXME: write description"
  :url "http://example.com/FIXME"

  :dependencies [[buddy "1.3.0"]
                 [compojure "1.5.2"]
                 [conman "0.6.3"]
                 [cprop "0.1.10"]
                 [funcool/struct "1.0.0"]
                 [luminus-immutant "0.2.3"]
                 [luminus-migrations "0.3.0"]
                 [luminus-nrepl "0.1.4"]
                 [markdown-clj "0.9.98"]
                 [metosin/muuntaja "0.1.0"]
                 [metosin/ring-http-response "0.8.2"]
                 [mount "0.1.11"]
                 [org.clojure/clojure "1.8.0"]
                 [org.clojure/tools.cli "0.3.5"]
                 [org.clojure/tools.logging "0.3.1"]
                 [org.postgresql/postgresql "42.0.0"]
                 [org.webjars.bower/tether "1.4.0"]
                 [org.webjars/bootstrap "4.0.0-alpha.5"]
                 [org.webjars/font-awesome "4.7.0"]
                 [org.webjars/jquery "3.1.1"]
                 [org.webjars/webjars-locator-jboss-vfs "0.1.0"]
                 [ring-webjars "0.1.1"]
                 [ring/ring-core "1.6.0-RC1"]
                 [ring/ring-defaults "0.2.3"]
                 [selmer "1.10.7"]
                 [overtone "0.10.1"]]

  :min-lein-version "2.0.0"

  :jvm-opts ["-server" "-Dconf=.lein-env"]
  :source-paths ["src/clj"]
  :test-paths ["test/clj"]
  :resource-paths ["resources"]
  :target-path "target/%s/"
  :main ^:skip-aot comusic.core
  :migratus {:store :database :db ~(get (System/getenv) "DATABASE_URL")}

  :plugins [[lein-cprop "1.0.1"]
            [migratus-lein "0.4.4"]
            [lein-immutant "2.1.0"]]

  :profiles
  {:uberjar       {:omit-source    true
                   :aot            :all
                   :uberjar-name   "comusic.jar"
                   :source-paths   ["env/prod/clj"]
                   :resource-paths ["env/prod/resources"]}

   :dev           [:project/dev :profiles/dev]
   :test          [:project/dev :project/test :profiles/test]



   :project/dev   {:dependencies   [[prone "1.1.4"]
                                    [ring/ring-mock "0.3.0"]
                                    [ring/ring-devel "1.5.1"]
                                    [pjstadig/humane-test-output "0.8.1"]]
                   :plugins        [[com.jakemccrary/lein-test-refresh "0.18.1"]]

                   :source-paths   ["env/dev/clj"]
                   :resource-paths ["env/dev/resources"]
                   :repl-options   {:init-ns user}
                   :injections     [(require 'pjstadig.humane-test-output)
                                    (pjstadig.humane-test-output/activate!)]}
   :project/test  {:resource-paths ["env/test/resources"]}
   :profiles/dev  {}
   :profiles/test {}})

EDIT: After booting a SC server and trying to connect to it in my main function I still get the same error. File which contains main function:

(ns comusic.core
  (:require [comusic.handler :as handler]
            [luminus.repl-server :as repl]
            [luminus.http-server :as http]
            [luminus-migrations.core :as migrations]
            [comusic.config :refer [env]]
            [clojure.tools.cli :refer [parse-opts]]
            [clojure.tools.logging :as log]
            [mount.core :as mount]
            [overtone.core :as overtone])
  (:gen-class))

(def cli-options
  [["-p" "--port PORT" "Port number"
    :parse-fn #(Integer/parseInt %)]])

(mount/defstate ^{:on-reload :noop}
                http-server
                :start
                (http/start
                  (-> env
                      (assoc :handler (handler/app))
                      (update :port #(or (-> env :options :port) %))))
                :stop
                (http/stop http-server))

(mount/defstate ^{:on-reload :noop}
                repl-server
                :start
                (when-let [nrepl-port (env :nrepl-port)]
                  (repl/start {:port nrepl-port}))
                :stop
                (when repl-server
                  (repl/stop repl-server)))


(defn stop-app []
  (doseq [component (:stopped (mount/stop))]
    (log/info component "stopped"))
  (shutdown-agents))

(defn start-app [args]
  (doseq [component (-> args
                        (parse-opts cli-options)
                        mount/start-with-args
                        :started)]
    (log/info component "started"))
  (.addShutdownHook (Runtime/getRuntime) (Thread. stop-app)))

(defn -main [& args]
  (cond
    (some #{"migrate" "rollback"} args)
    (do
      (mount/start #'comusic.config/env)
      (migrations/migrate args (select-keys env [:database-url]))
      (System/exit 0))
    :else
    (do
      (overtone/connect-external-server 57110)
      (start-app args))))