Access tokens are an important part of granting access to a user. Access Tokens are part of the Auth2.0 standard. It is issued after successful login and contains information about the user's authorizations. Access token contains user information such as which groups the user belongs to, which roles the user has , the  scopes  of  the user , user privileges,  access rights and access permissions   

It is possible that if there is a problem with your Access Tokens you can be denied access. We have identified a scenario where your access has been denied and the following error messages are appearing. 



In this particular scenario the access has been denied because the access tokens contained XML. The core of XML is in its name: Extensible Markup Language. XML is extensible. XML is a meta-language, a language that allows us to create or define other languagesIt is widely used as a data conversion language. To compare    with    an example HTML is a simple predefined language, while XML is a standard language that defines other languages. So yes, when your tokens contain not   simple    language    but meta-language it can    sometimes  lead to access being denied. In such instances access tokens are rendered invalid    preventing you from access.    

So please check that the   access tokens   do not contain   XML   and you are good to go!