This KB is to guide the customer when using the windows based FTP on issues and possible steps proceed with.
Symptoms:
VMware Cloud Foundation 4.4.1
VMware Cloud Foundation 5.x
SSDC manager Backup & Restore is validated with Cygwin based OpenSSH.
So as a consequence - SDDC manager supports the Windows sftp as long as it is OpenSSH based.
Work with your external vendor to see the deviation from openSSH(using standard OpenSSH implementation) and get it resolved. Alternatively you may use Linux sftp.
Workaround:
External sftp is outside VCF. So VCF has little control over the specific implementations of the sftp and their deviations compared to OpenSSH(Cygwin OpenSSH for example). Please work with third party sftp vendor for the resolution.