rails g controller実行時に"Could not find racc-1.5.2 in any of the sources (Bundler::GemNotFound)"のエラー

前提・実現したいこと

railsで"rails g controller home top"を実行したい。
初学者です。
railsの環境構築中です。
railsのサーバーを起動して、アクセス（ブラウザで表示）することはできていますが、
アプリケーションにcontrollerを作成するタイミングでエラーが発生します。

OS:macOS Catalina 10.15.5
Ruby: ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin19]
rbenv: 1.1.2
Rails: 6.1.1

発生している問題・エラーメッセージ

$ rails g controller home top
上記実行時に下記エラーが発生する。
Could not find racc-1.5.2 in any of the sources (Bundler::GemNotFound)

該当のソースコード

:sample_app XXXX$ rails g controller home top
Traceback (most recent call last):
22: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/bin/spring:49:in <main>' 21: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/client.rb:30:in run'
20: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/client/command.rb:7:in call' 19: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/client/server.rb:9:in call'
18: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require' 17: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require'
16: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/server.rb:9:in <top (required)>' 15: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require'
14: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require' 13: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/commands.rb:4:in <top (required)>'
12: from /Library/Ruby/Gems/2.6.0/gems/spring-2.1.1/lib/spring/commands.rb:33:in <module:Spring>' 11: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require'
10: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in require' 9: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/setup.rb:20:in <top (required)>'
8: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler.rb:107:in setup' 7: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/runtime.rb:20:in setup'
6: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/runtime.rb:108:in block in definition_method' 5: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/definition.rb:226:in requested_specs'
4: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/definition.rb:237:in specs_for' 3: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/definition.rb:170:in specs'
2: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/spec_set.rb:85:in materialize' 1: from /Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/spec_set.rb:85:in map!'
/Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/2.6.0/bundler/spec_set.rb:91:in `block in materialize': Could not find racc-1.5.2 in any of the sources (Bundler::GemNotFound)


### 試したこと

・racc-1.5.2が見つからないようだったので、racc-1.5.2を個別にインストール

$ bundle show raccの実行結果↓

The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
/Users/XXXX/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/racc-1.5.2


・gem list↓

*** LOCAL GEMS ***

actioncable (6.1.1)
actionmailbox (6.1.1)
actionmailer (6.1.1)
actionpack (6.1.1)
actiontext (6.1.1)
actionview (6.1.1)
activejob (6.1.1)
activemodel (6.1.1)
activerecord (6.1.1)
activestorage (6.1.1)
activesupport (6.1.1)
addressable (2.7.0)
bigdecimal (default: 1.4.1)
bindex (0.8.1)
bootsnap (1.7.1)
builder (3.2.4)
bundler (2.2.9, default: 1.17.2)
byebug (11.1.3)
capybara (3.35.3)
childprocess (3.0.0)
cmath (default: 1.0.0)
concurrent-ruby (1.1.8)
crass (1.0.6)
csv (default: 3.0.9)
date (default: 2.0.0)
dbm (default: 1.0.0)
did_you_mean (1.3.0)
e2mmap (default: 0.1.0)
erubi (1.10.0)
etc (default: 1.0.1)
fcntl (default: 1.0.0)
ffi (1.14.2)
fiddle (default: 1.0.0)
fileutils (default: 1.1.0)
forwardable (default: 1.2.0)
globalid (0.4.2)
i18n (1.8.8)
io-console (default: 0.4.7)
ipaddr (default: 1.2.2)
irb (default: 1.0.0)
jbuilder (2.11.2)
json (default: 2.1.0)
listen (3.4.1)
logger (default: 1.3.0)
loofah (2.9.0)
mail (2.7.1)
marcel (0.3.3)
matrix (default: 0.1.0)
method_source (1.0.0)
mimemagic (0.3.5)
mini_mime (1.0.2)
mini_portile2 (2.5.0)
minitest (5.14.3, 5.11.3)
msgpack (1.4.2)
mutex_m (default: 0.1.0)
net-telnet (0.2.0)
nio4r (2.5.5)
nokogiri (1.11.1 x86_64-darwin)
openssl (default: 2.1.2)
ostruct (default: 0.1.0)
power_assert (1.1.3)
prime (default: 0.1.0)
psych (default: 3.1.0)
public_suffix (4.0.6)
puma (5.2.1)
**racc (1.5.2)**
rack (2.2.3)
rack-mini-profiler (2.3.1)
rack-proxy (0.6.5)
rack-test (1.1.0)
rails (6.1.1)
rails-dom-testing (2.0.3)
rails-html-sanitizer (1.3.0)
railties (6.1.1)
rake (13.0.3, 12.3.2)
rb-fsevent (0.10.4)
rb-inotify (0.10.1)
rdoc (default: 6.1.0)
regexp_parser (2.0.3)
rexml (default: 3.1.9)
rss (default: 0.2.7)
rubyzip (2.3.0)
sass-rails (6.0.0)
sassc (2.4.0)
sassc-rails (2.1.2)
scanf (default: 1.0.0)
sdbm (default: 1.0.0)
selenium-webdriver (3.142.7)
semantic_range (2.3.1)
shell (default: 0.7)
spring (2.1.1)
sprockets (4.0.2)
sprockets-rails (3.2.2)
sqlite3 (1.4.2)
stringio (default: 0.0.2)
strscan (default: 1.0.0)
sync (default: 0.5.0)
test-unit (3.2.9)
thor (1.1.0)
thwait (default: 0.1.0)
tilt (2.0.10)
tracer (default: 0.1.0)
turbolinks (5.2.1)
turbolinks-source (5.2.0)
tzinfo (2.0.4)
web-console (4.1.0)
webdrivers (4.5.0)
webpacker (5.2.1)
webrick (default: 1.4.2)
websocket-driver (0.7.3)
websocket-extensions (0.1.5)
xmlrpc (0.3.0)
xpath (3.2.0)
zeitwerk (2.4.2)
zlib (default: 1.0.0)


### 補足情報（FW/ツールのバージョンなど）
OS:macOS Catalina 10.15.5
Ruby: ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin19]
rbenv: 1.1.2
Rails: 6.1.1