Delimiter error when using Logstash File Input Plugin. Files not ingested fully

[dx123]

I'm using the Logstash File Input Plugin to ingest a a file but I am receiving this error:

[[main]<file] readfile - buffer_extract: a delimiter can't be found in current chunk, maybe there are no more delimiters or the delimiter is incorrect or the text before the delimiter, a 'line', is very large, if this message is logged often try increasing the file_chunk_size setting. {"delimiter"=>"\n", "read_position"=>0, "bytes_read_count"=>2661945, "last_known_file_size"=>2661945, "file_path"=>"/Desktop/test.json"}

I'm not sure if it is due to the above error, but Logstash is hence unable to ingest all of the events in the file. I have tried many variations of the config but to no avail. Below is my config:

input {
	file {
		path => [ "/Desktop/test.json" ]
	    mode => "read"
		codec => "json"
		file_completed_action => "log"
		file_completed_log_path => "/Desktop/logstash_completed_files.txt"
		sincedb_path => "/dev/null"
		file_chunk_size => 104857600
		file_chunk_count => 100
	}
}

Anyone able to explain what the delimiter error means and how to fix it? Thanks!