Narou.rb のバージョン：
3.7.2
OS のバージョン：
macOS BigSur 11.4（20F71）
何が起きたのか：
小説の更新までは出来るが小説の変換が出来ません
途中で固まってしまう？
再現方法（何をやったら起こったのか詳細に）：
WEBUIで変換しようとしたところこうなっていることに気が付きました
具体的にいつから発生していたかはわかりません。ブラウザはSafariですがChromeで試しても不可能でした。
- - [15/Jun/2021:20:55:30 JST] "POST /api/convert HTTP/1.1" 200 0
ttp://192.168.0.4:5678/ -> /api/convert
#<Thread:0x00007fe3212ec2d0@/Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/web/web_worker.rb:46 run> terminated with exception (report_on_exception is true):
Traceback (most recent call last):
31: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/web/web_worker.rb:47:in `block (3 levels) in start'
30: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/web/appserver.rb:528:in `block (2 levels) in <class:AppServer>'
29: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/commandline.rb:43:in `run!'
28: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/commandline.rb:29:in `run'
27: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:122:in `execute!'
26: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/narou.rb:369:in `concurrency_call'
25: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:123:in `block in execute!'
24: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/commandbase.rb:134:in `execute!'
23: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/commandbase.rb:125:in `execute!'
22: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:133:in `execute'
21: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:152:in `main'
20: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:152:in `each'
19: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:159:in `block in main'
18: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:199:in `convert_novels'
17: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:199:in `with_index'
16: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:199:in `each'
15: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/command/convert.rb:200:in `block in convert_novels'
14: from /Users/aaaa/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/narou-3.7.2/lib/mixin/locker.rb:26:in `lock'
