Hi David Montoya,

I am really sorry for the delay of this reply as it is a weekend for us here.

Yes, this is common because sometime they provided some special character from their credential, then we will get login failed.
And another possibility as you mentioned above is depend on that person how he copy the credentials, e.g when you highlight, sometime it will including the space from the last word "password " , so this "space" also consider a character hence during the authentication, it will login failed because the password did not match.

I suppose, then that any provided credentials should be strictly alphanumeric. If admins don't want to share their own personal passwords, they can always make a new Super User login specifically for SI and also make a different FTP login rather than share their main account credentials. I find a lot of new developers aren't aware of the latter. This can help:

http://support.hostgator.com/articles/how-to-create-an-ftp-account-in-cpanel

Thanks for sharing this David