on SFTP server Public Key Authentication is enabled. If i try sftp connection from command line public key exchange works. If i try sftp connection with Pega connector SFTP or Test Connectivity on Pega FTP Server I receive error "No Configuration was registered that can handle the configuration named com.sun.security.jgss.krb5.initiate". Do Pega use settings on ssh_config file stored in /etc/ssh?
Based on the helpful information you have posted here, it appears to me that you may have encountered a previously undiscovered defect in the SFTP connectivity feature of Pega 7.3.1, and it should be investigated by Pega.
Please reach out to Global Customer Support at your earliest convenience, and cite this post when doing so.