FLASH error (string contains whitespace)

Hi there,
I do have problem using FLASH tool. It’s never shown up so I’m not sure what to do. After running FLASH I get this information: “[FLASH] ERROR: Invalid sequence string: contains whitespace, near line 85856937)”.
Does anyone know what to do with it? I would appreciate any advice.

There is something wrong with your input. If you have access to a command line interface you could do
sed -n '85856937p' < input.fastq to investigate.