EC
Encoding::ConverterNotFoundError
RubyERRORCriticalEncoding

No converter available between encodings

Quick Answer

Verify the encoding name is correct and supported; use Encoding.list to see available encodings.

What this means

Raised when Ruby cannot find a converter to transcode between two specified encodings. This can happen with obscure or non-standard encoding names.

Why it happens
  1. 1Specifying a misspelled or non-existent encoding name
  2. 2Attempting conversion between two encodings with no direct or indirect path

Fix

List available encodings and correct the name

List available encodings and correct the name
Encoding.list.map(&:name).sort.grep(/UTF/)
# Find the exact encoding name, then use it:
str.encode('UTF-8')

Why this works

Encoding.list returns all encodings Ruby knows about, helping you find the correct name.

Code examples
Reproducing the errorruby
'hello'.encode('FAKE-ENCODING')
# Encoding::ConverterNotFoundError: code converter not found (FAKE-ENCODING)
List available encodingsruby
Encoding.list.first(5).map(&:name)
# => ["ASCII-8BIT", "UTF-8", "US-ASCII", "UTF-16BE", ...]
Rescue itruby
begin
  str.encode(requested_encoding)
rescue Encoding::ConverterNotFoundError
  str.encode('UTF-8')   # fallback
end
Sources
Official documentation ↗

Ruby Core Documentation

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