Connection can not be established. Server name, port number, or credentials may be invalid.
I just got that message when trying to enter a perfectly valid set of connection/credential info into an SSIS package. But testing the connection failed.
Turns out my issue, and maybe your issue too, is that SSIS doesn’t remove white space from the server name textbox. So if you pasted in the name of the FTP server, as I did, you might have fallen victim to the “trailing space” that is frequently copied with your text, and instead of trying to connect to “ftp.com” it tried to connect to “ftp.com ” notice the extra space.
Chris May 
Chris:
I have a question that you may help me I used the FTP Task and it work in development with the user name and password but when I load the Job with the SSIS task it give me a error on FTP connection
Any Ideas?
Bill
The only thing I can think of is that it’s possible that the username and password are not being transferred to the ssis package. You might want to make sure that you have it saving that data.
Also, you’ll want to make sure that you production machine can create outbound FTP connections. Many antivirus programs block this (not to mention firewalls).