As Joachim mentioned, I would highly recommend installing the Single Sign-On SAP Browser Passport. Here is some more information: Simplify Your Login | SAP Support Portal
There are a variety of authentication points throughout the Launchpad and the Support Portal (including legacy applications that have not yet been replaced in the Launchpad). The Passport will help you to circumvent logging in each time. It's also helpful should you find yourself working with more than one login ID (e.g. for partners managing customer accounts).
If this does not resolve your issue, I would try closing your browser, clearing your cache and starting the login process over. Please let me know if this resolves the issue.
Best,
Jamie