sendRedirect to suitelet is not working I have external suitlet with login authenticator, after user will put credentials he will redirect to the same suitlet but in different context (using parameters to know what context he will get, need to log or already logged) i get "*Invalid page parameter. Unable to view page.* " Netsuite error.

response.sendRedirect({
                            type: 'SUITELET',
                            id: 'customdeploy_tpp_su',
                            identifier: 'customscript_tpp_su',
                            parameters: {
                                custparam_action: 'dashboard',
                                custparam_sessionid: sessionId
                            }
                        });

All IDs, are ok. Suitlet is "Available without login"

is it set to RELEASED or TEST...

release

Have you enabled the "Available Without Login" check or tried giving access to external roles in the deploy?

If you have it set to available without login, as you stated, take a look at the external users list you probably need to choose one of the options there on the deployment.