Cant Import into leads

Cant Import into leads

I have imported data previously with no issues

The last 2 days I have been trying to import leads from a .csv file and keep getting the following message even though all fields have data and no fields have any special characters in them. I have gone through the importing data checklist and still cant find the issue. Would like some assistance. thanks

" (Reason: Due to empty values for any of the mandatory fields)"