I am importing contributions from my donors from a .csv file. I have tested the process using a simple .csv file with one row of data for a payment from a donor I have already added to contacts. The import was successful, matching the contribution to the donor. When I try to repeat this process using a spreadsheet with approximately 40 rows of data (including multiple contributions from some donors) all rows of the spreadsheet fail to import and have the error message 'Expected one Contribution but found 2'. I am using the email address to match to contact.
Any ideas what I am doing wrong?