10.2.2.5. Error Documents

To use a hard-coded message with the ErrorDocument directive, the message should be enclosed in a pair of double quotation marks ", rather than just preceded by a double quotation mark as required in Apache HTTP Server 1.3.
For example, the following is a sample Apache HTTP Server 1.3 directive:
ErrorDocument 404 "The document was not found
To migrate an ErrorDocument setting to Apache HTTP Server 2.0, use the following structure:
ErrorDocument 404 "The document was not found"
Note the trailing double quote in the previous ErrorDocument directive example.
For more on this topic, refer to the following documentation on the Apache Software Foundation's website: