300 new customer accounts to set up and the upload customer from spreadsheet function keeps erroring

Due to an upgrade of another system we will have over 300 new customers to upload this week, but the spreadsheet function keeps erroring.

We now have multiple entries with a status of process error and any subsequent uploads are now failing too.

Do we need to purge / abort failed processes to get this to work, are the failed ones blocking new ones?

I will upload the error log, does anyone know what the problem is with the file?

many thanks Lisa