Farhad did you use the same email account before? Typical causes:
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the SFDC User name and email address can be different, so if you have the wrong one you'll reeive an error like this.
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If you copy and paste the password or token from an email, you may be inadvertently adding spaces
Beyond that, I'd recommend walking through the sync steps and double-checking the data
http://community.marketo.com/MarketoArticle?id=kA050000000KyrUCAS