Howto purchase GitLab certifications

Hello, i want to enroll into the “GitLab Certified Git Associate Exam” and i would need some guidance since i am failing to purchase the exam.

Once i choose the exam i would like to purchase GitLab Certifications and click on checkout GitLab Certified Git Associate Exam - GitLab

but then i get redirected to my project without the option to purchase it. Please help!