I have an odd issue that came up. I have a PowerShell script that is connecting to an FTP site using the .Net assembly (WinSCP.Session). The FTP connection is over SSL using implicit encryption. The script was connecting without issue both in test (Windows 2016) and production (Windows 2008 R2). The connection info was the same for both environments. We have three different processes that are connecting to the same FTP site. The only difference is, they are using different credentials and downloading different files.
On Sunday, the production server was cut over to Windows 2016. After the cutover when those scripts executed, each one failed with Peer certificate rejected. I had to add the certificate fingerprint (TlsHostCertificateFingerprint) to the session object to each of the scripts in order for them to connect.
At first I thought it was something with the source FTP server, but when I connect from test (without TlsHostCertificateFingerprint added to the session object), I connected without issue.
There is one process that uses Winscp.com with a command file that opens a saved site. It did not have issues.
The version of WinSCP (5.15.9 build 10071) is the same for all three environments (old prod, new prod, and test).
Do you have any idea as to why this occurred? Thanks!