Hi,
I had the same issue. Here are some suggestions:
1) I am going to assume you might be using Mac vs. PC.
2) Using Mac Excel, create a .csv file with the source URL in Column A and the target URL in Column B. Do not enter any header in row 1.
3) Using Mac Excel, save the file as a Windows Comma Separated (.csv) format. Do not select Comma Separated Values (.csv) or MS-DOS Comma Separated Values (.csv)
4) In the Redirections Plugin, select Options, under Import Choose File, click Upload.
If you don’t have the correct .csv format, the Redirection Plugin will import only one row. Make sure you count the number of rows before you import to ensure all of your redirects were imported.
Good luck to you!