Hi Barayang,
Once you have claimed your exam discount, please click on the Schedule Exam ‘blue’ button at the lower right-hand side to be redirected to the exam delivery provider’s portal for exam registration.

Furthermore, we would like for you to re-try the troubleshooting steps provided below:
Use Edge Chromium (Edge 88.0) or Google Chrome (version 88.0), including InPrivate and Incognito browsing modes. Note: Please make sure that the browsers that you will use are running on the latest version to resolve any compatibility issues.
Clear your cached data and cookies.
Allow all third-party cookies through your site permission settings.
If that did not work, please send us a PSR (Problem Steps Recorder) which includes all the steps provided above (including your login to your dashboard) until your reach an error message (if any).
Please send this through the private message I have initiated, along with your answers to our request for at least three (3) important pieces of account information to verify your profile. Kindly refer to the image below to view the message sent:

I look forward to your response. Please note that if no response has been received after two business days, the case will be closed and locked. After the case is locked, we will no longer be able to respond, even through Private Messages. Thank you.
All the best,