Exception in thread "main" clojure.lang.ExceptionInfo: Error in component :listener in system com.stuartsierra.component.SystemMap calling #'com.stuartsierra.component/start {:reason :com.stuartsierra.component/component-function-threw-exception, :function #'com.stuartsierra.component/start, :system-key :listener, :component #web.core.Listener{:listener nil}, :system #<SystemMap>}, compiling:(/tmp/form-init7411312467703964054.clj:1:73)
2017-03-13T14:18:34.518986+00:00 app[web.1]: at clojure.lang.Compiler.load(Compiler.java:7391)
2017-03-13T14:18:34.519021+00:00 app[web.1]: at clojure.lang.Compiler.loadFile(Compiler.java:7317)
2017-03-13T14:18:34.519050+00:00 app[web.1]: at clojure.main$load_script.invokeStatic(main.clj:275)
2017-03-13T14:18:34.519088+00:00 app[web.1]: at clojure.main$init_opt.invokeStatic(main.clj:277)
2017-03-13T14:18:34.519125+00:00 app[web.1]: at clojure.main$init_opt.invoke(main.clj:277)
2017-03-13T14:18:34.519157+00:00 app[web.1]: at clojure.main$initialize.invokeStatic(main.clj:308)
2017-03-13T14:18:34.519190+00:00 app[web.1]: at clojure.main$null_opt.invokeStatic(main.clj:342)
2017-03-13T14:18:34.519229+00:00 app[web.1]: at clojure.main$null_opt.invoke(main.clj:339)
2017-03-13T14:18:34.519266+00:00 app[web.1]: at clojure.main$main.invokeStatic(main.clj:421)
2017-03-13T14:18:34.519300+00:00 app[web.1]: at clojure.main$main.doInvoke(main.clj:384)
2017-03-13T14:18:34.519344+00:00 app[web.1]: at clojure.lang.RestFn.invoke(RestFn.java:421)
2017-03-13T14:18:34.519372+00:00 app[web.1]: at clojure.lang.Var.invoke(Var.java:383)
2017-03-13T14:18:34.519450+00:00 app[web.1]: at clojure.lang.AFn.applyToHelper(AFn.java:156)
2017-03-13T14:18:34.632589+00:00 heroku[web.1]: Process exited with status 1
2017-03-13T14:18:34.519503+00:00 app[web.1]: at clojure.lang.Var.applyTo(Var.java:700)
2017-03-13T14:18:34.519564+00:00 app[web.1]: at clojure.main.main(main.java:37)
2017-03-13T14:18:34.519947+00:00 app[web.1]: Caused by: clojure.lang.ExceptionInfo: Error in component :listener in system com.stuartsierra.component.SystemMap calling #'com.stuartsierra.component/start {:reason :com.stuartsierra.component/component-function-threw-exception, :function #'com.stuartsierra.component/start, :system-key :listener, :component #web.core.Listener{:listener nil}, :system #<SystemMap>}
2017-03-13T14:18:34.520007+00:00 app[web.1]: at clojure.core$ex_info.invokeStatic(core.clj:4617)
2017-03-13T14:18:34.520035+00:00 app[web.1]: at clojure.core$ex_info.invoke(core.clj:4617)
2017-03-13T14:18:34.520098+00:00 app[web.1]: at com.stuartsierra.component$try_action.invokeStatic(component.cljc:119)
2017-03-13T14:18:34.520153+00:00 app[web.1]: at com.stuartsierra.component$try_action.invoke(component.cljc:116)
2017-03-13T14:18:34.520215+00:00 app[web.1]: at com.stuartsierra.component$update_system$fn__27520.invoke(component.cljc:139)
2017-03-13T14:18:34.520267+00:00 app[web.1]: at clojure.lang.ArraySeq.reduce(ArraySeq.java:109)
2017-03-13T14:18:34.520327+00:00 app[web.1]: at clojure.core$reduce.invokeStatic(core.clj:6544)
2017-03-13T14:18:34.520377+00:00 app[web.1]: at clojure.core$reduce.invoke(core.clj:6527)
2017-03-13T14:18:34.520400+00:00 app[web.1]: at com.stuartsierra.component$update_system.invokeStatic(component.cljc:135)
2017-03-13T14:18:34.520430+00:00 app[web.1]: at com.stuartsierra.component$update_system.doInvoke(component.cljc:129)
2017-03-13T14:18:34.520458+00:00 app[web.1]: at clojure.lang.RestFn.invoke(RestFn.java:445)
2017-03-13T14:18:34.520536+00:00 app[web.1]: at com.stuartsierra.component$start_system.invokeStatic(component.cljc:163)
2017-03-13T14:18:34.520610+00:00 app[web.1]: at com.stuartsierra.component$start_system.invoke(component.cljc:155)
2017-03-13T14:18:34.520729+00:00 app[web.1]: at com.stuartsierra.component$start_system.invokeStatic(component.cljc:161)
2017-03-13T14:18:34.520800+00:00 app[web.1]: at com.stuartsierra.component$start_system.invoke(component.cljc:155)
2017-03-13T14:18:34.520855+00:00 app[web.1]: at com.stuartsierra.component.SystemMap.start(component.cljc:178)
2017-03-13T14:18:34.520969+00:00 app[web.1]: at web.core$_main.invokeStatic(core.clj:71)
2017-03-13T14:18:34.521016+00:00 app[web.1]: at web.core$_main.doInvoke(core.clj:69)
2017-03-13T14:18:34.521069+00:00 app[web.1]: at clojure.lang.RestFn.invoke(RestFn.java:397)
2017-03-13T14:18:34.521135+00:00 app[web.1]: at clojure.lang.Var.invoke(Var.java:375)
2017-03-13T14:18:34.521191+00:00 app[web.1]: at user$eval5.invokeStatic(form-init7411312467703964054.clj:1)
2017-03-13T14:18:34.521250+00:00 app[web.1]: at user$eval5.invoke(form-init7411312467703964054.clj:1)
2017-03-13T14:18:34.521308+00:00 app[web.1]: at clojure.lang.Compiler.eval(Compiler.java:6927)
2017-03-13T14:18:34.521366+00:00 app[web.1]: at clojure.lang.Compiler.eval(Compiler.java:6917)
2017-03-13T14:18:34.521435+00:00 app[web.1]: at clojure.lang.Compiler.load(Compiler.java:7379)
2017-03-13T14:18:34.521530+00:00 app[web.1]: ... 14 more
2017-03-13T14:18:34.521743+00:00 app[web.1]: Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentCollection
2017-03-13T14:18:34.521785+00:00 app[web.1]: at clojure.core$conj__4345.invokeStatic(core.clj:82)
2017-03-13T14:18:34.521814+00:00 app[web.1]: at clojure.core$merge$fn__4877.invoke(core.clj:2940)
2017-03-13T14:18:34.521851+00:00 app[web.1]: at clojure.core$reduce1.invokeStatic(core.clj:925)
2017-03-13T14:18:34.521885+00:00 app[web.1]: at clojure.core$reduce1.invokeStatic(core.clj:915)
2017-03-13T14:18:34.521922+00:00 app[web.1]: at clojure.core$merge.invokeStatic(core.clj:2939)
2017-03-13T14:18:34.521955+00:00 app[web.1]: at clojure.core$merge.doInvoke(core.clj:2932)
2017-03-13T14:18:34.521988+00:00 app[web.1]: at clojure.lang.RestFn.invoke(RestFn.java:421)
2017-03-13T14:18:34.522026+00:00 app[web.1]: at yada.aleph$listener.invokeStatic(aleph.clj:15)
2017-03-13T14:18:34.522048+00:00 app[web.1]: at yada.aleph$listener.doInvoke(aleph.clj:8)
2017-03-13T14:18:34.522076+00:00 app[web.1]: at clojure.lang.RestFn.invoke(RestFn.java:423)
2017-03-13T14:18:34.522103+00:00 app[web.1]: at web.core.Listener.start(core.clj:29)
2017-03-13T14:18:34.522131+00:00 app[web.1]: at com.stuartsierra.component$eval27461$fn__27462$G__27451__27464.invoke(component.cljc:5)
2017-03-13T14:18:34.522169+00:00 app[web.1]: at com.stuartsierra.component$eval27461$fn__27462$G__27450__27467.invoke(component.cljc:5)
2017-03-13T14:18:34.522203+00:00 app[web.1]: at clojure.lang.Var.invoke(Var.java:379)
2017-03-13T14:18:34.522224+00:00 app[web.1]: at clojure.lang.AFn.applyToHelper(AFn.java:154)
2017-03-13T14:18:34.522252+00:00 app[web.1]: at clojure.lang.Var.applyTo(Var.java:700)
2017-03-13T14:18:34.522302+00:00 app[web.1]: at clojure.core$apply.invokeStatic(core.clj:648)
2017-03-13T14:18:34.522386+00:00 app[web.1]: at clojure.core$apply.invoke(core.clj:641)
2017-03-13T14:18:34.522493+00:00 app[web.1]: at com.stuartsierra.component$try_action.invokeStatic(component.cljc:117)
2017-03-13T14:18:34.522562+00:00 app[web.1]: ... 36 more
2017-03-13T14:18:34.643501+00:00 heroku[web.1]: State changed from starting to crashed
I think you may be right about (:env port) as there is the error "Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentCollection"