Need help getting SFTP working

SBOP BI 4.2 SP05

I have followed the instructions in KBA 2183131 to obtain our customer's SFTP server's fingerprint. The connection works. Through FileZilla I can see the file being created on their SFTP server. However the job fails with this error:

"destination_sftp: exception caught while putting source file [D:\SAP\SAP BusinessObjects Enterprise XI 4.0\Data\procSched\GPSAPBIPROD.AdaptiveJobServer\~ce2f349a0c7993691.xlsx] to sftp server [ftp1.<removed>.com] as destination file [/uploads/test.xlsx]. Details: [Something went wrong while writing data. Please try again]"

When we send the exact same file over FileZilla it works fine. So I am at a loss as to what could be causing the problem. The customer says they have other vendors who send them files via SFTP but none that use SAP to do so. This is a Crystal Reports generated Excel file we are trying to upload.

Please help. TIA