Takes forever to start up

I'm trying to implement examples from the open source book Modern CLJS

I've already write a runnable boot task to compile, watch and serve my project, here's code for build.boot:

; vim: set ft=clojure:

(set-env!
 :source-paths #{"src/cljs"}
 :resource-paths #{"html"}

 :dependencies '[[org.clojure/clojure "1.10.3"]         ;; add CLJ
                 [org.clojure/clojurescript "1.10.866"] ;; add CLJS
                 [adzerk/boot-cljs "2.1.5"]
                 [pandeiro/boot-http "0.8.3"]
                 [org.clojure/tools.nrepl "0.2.13"]
                 [adzerk/boot-reload "0.6.1"]
                 [adzerk/boot-cljs-repl "0.4.0"]
                 [cider/piggieback "0.3.9"]            ;; needed by bREPL
                 [weasel "0.7.1"]])                    ;; needed by bREPL

(require '[adzerk.boot-cljs :refer [cljs]]
         '[pandeiro.boot-http :refer [serve]]
         '[adzerk.boot-reload :refer [reload]]
         '[adzerk.boot-cljs-repl :refer [cljs-repl start-repl]])

(deftask dev
  "Launch Immediate Feedback Development Environment"
  []
  (comp
    (serve :dir "target")
    (watch)
    (reload)
    (cljs-repl)
    (cljs)
    (target :dir #{"target"})))

I set up my interactive development environment by running the followings in different consoles:

boot dev 
boot repl -c

In the boot repl, I typed (start-repl), which, however, takes forever to finish and block my input. Like this:

<< started Weasel server on ws://127.0.0.1:39371 >>
<< waiting for client to connect ... Connection is ws://localhost:39371
Writing boot_cljs_repl.cljs...

However, it's wired since I once successfully start the bREPL, yet now I can't.

nrepl / weasel

Takes forever to start up #77