I can't upload contacts into SurveyLab

If you can't upload a list of contacts into SurveyLab, please check :

1. If your file does contain blank lines.
2. If your file contains special characters inside contacts.

If your file contains blank lines please delete them.

To do it you can use MS Excel :

1. Open your file in the Excel.
2. Sort it.
3. Save your file.