500 Internal Server Error

cannot load such file -- bundler/setup (LoadError)

<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
/usr/home/wbsrvr/web2/diary/lib/tdiary/environment.rb:8:in `<top (required)>'
<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
/usr/home/wbsrvr/web2/diary/lib/tdiary.rb:25:in `<top (required)>'
<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/usr/local/lib/ruby/3.1/rubygems/core_ext/kernel_require.rb>:85:in `require'
/usr/home/wbsrvr/web2/diary/index.rb:18:in `<main>'