An open redirect is an application that takes a parameter and redirects a user to the parameter value without any validation. This vulnerability is used in phishing attacks to get users to visit malicious sites without realizing it.
its possible to bypass your redirect filter using : https://www.zaption.com/logout?returnTo=///evil.com/
<p>Moved Temporarily. Redirecting to <a href="///evil.com">///evil.com</a></p>`