error while running gtk-api

[VivekJaganath]

i am running below error while running gtk-api.

/app/models/mano_manager_service.rb:34: warning: previous definition of LOG_MESSAGE was here

• Gracefully stopping, waiting for requests to finish
  ! Unable to load application: NoMethodError: undefined method stop' for nil:NilClass bundler: failed to load command: puma (/usr/local/bundle/bin/puma) NoMethodError: undefined method stop' for nil:NilClass
  /usr/local/bundle/gems/puma-3.11.0/lib/puma/single.rb:28:in stop_blocked' /usr/local/bundle/gems/puma-3.11.0/lib/puma/launcher.rb:291:in graceful_stop'
  /usr/local/bundle/gems/puma-3.11.0/lib/puma/launcher.rb:395:in block in setup_signals' /app/gtk_api.rb:112:in kill'
  /app/gtk_api.rb:112:in block in <class:GtkApi>' /app/gtk_api.rb:98:in each'
  /app/gtk_api.rb:98:in <class:GtkApi>' /app/gtk_api.rb:53:in <top (required)>'
  config.ru:28:in require' config.ru:28:in block in '
  /usr/local/bundle/gems/rack-2.0.7/lib/rack/builder.rb:55:in instance_eval' /usr/local/bundle/gems/rack-2.0.7/lib/rack/builder.rb:55:in initialize'
  config.ru:in new' config.ru:in '
  /usr/local/bundle/gems/rack-2.0.7/lib/rack/builder.rb:49:in eval' /usr/local/bundle/gems/rack-2.0.7/lib/rack/builder.rb:49:in new_from_string'
  /usr/local/bundle/gems/rack-2.0.7/lib/rack/builder.rb:40:in parse_file' /usr/local/bundle/gems/puma-3.11.0/lib/puma/configuration.rb:318:in load_rackup'
  /usr/local/bundle/gems/puma-3.11.0/lib/puma/configuration.rb:243:in app' /usr/local/bundle/gems/puma-3.11.0/lib/puma/runner.rb:138:in load_and_bind'
  /usr/local/bundle/gems/puma-3.11.0/lib/puma/single.rb:87:in run' /usr/local/bundle/gems/puma-3.11.0/lib/puma/launcher.rb:183:in run'
  /usr/local/bundle/gems/puma-3.11.0/lib/puma/cli.rb:77:in run' /usr/local/bundle/gems/puma-3.11.0/bin/puma:10:in <top (required)>'
  /usr/local/bundle/bin/puma:29:in load' /usr/local/bundle/bin/puma:29:in <top (required)>'