java - JAXB Exception: Class not known to this context while marshalling

Question

I am getting below error while marshalling. I generated xml's from schemas.

[javax.xml.bind.MarshalException
- with linked exception:
[com.sun.istack.internal.SAXException2: class org.com.AccountsComplexType nor any of its super class is known to this context.

After a little research, some people says "Try adding @XmlSeeAlso(...class)" but the problem is AccountsComplexType class is not a XmlRootElement.

Is there any idea what am I doing wrong?