[74545]ERROR:plugins.FtpStorageIOLib:ftps cmd failed. RC: 64, Err: curl: (64) Requested SSL level failed
, Cmd: ['/usr/bin/curl', '--fail', '-u', 'ftpuser:****', '--connect-timeout', '120', '--ssl-reqd', '-k', '--noproxy', '*', '--silent', '--show-error', '--list-only', 'ftp://<FTP_SERVER>/Backups/']
[74545]ERROR:vmware.appliance.vapi.impl:pint.Error('com.vmware.applmgmt.backup.plugin.internal_server_err', 'General system error reported by backup server.', **{'args': ['Plugin error occurred. ErrCode: 5, Args: ()']})
[74545]INFO:cis.vpxdevent_lib:Event com.vmware.applmgmt.backup.job.failed.event successfully posted to http://localhost:8085/sdk
Error message " RC: 64, Err: curl: (64) Requested SSL level failed" indicates backup workflow was not able to setup SSL enabled connection with the configured remote FTP Server.
For FTPS protocol, backup workflow explicitly enables TLS connection via using AUTH TLS command. The above error suggests, the remote FTP server did not respond correctly to this command.
Check the configuration on the remote FTP server and make sure it is correctly setup for FTPS connections. One of the common scenario of the failure can be expiry of the SSL certificates used for FTPS, on the remote FTP Server.
If remote FTP server no longer support TLS connections, switch the backup configuration to use FTP protocol.
For a failure with similar error message but using SFTP protocol, read the following knowledgebase articles for guidance.