You should start with the external file load information - looking at the details. 

If for example, you had external file template control using skip or satisfy, and the controls result in no records, that could easily be a reason.  

Also, if the data was an excel sheet, that may also produce the same error.  Follow the flow and compare to the template. 

I removed the skip and still receive the error.  The file is a .csv.

Take a look at the external file - monitor external files - see the load and the details.   

Check the template, and verify the delimiters. For example if the delimiter is ;  and the data has comma, it’s probably not going to find any valid records.