Hello ZAMAN,
Thank you for contacting the Microsoft Community.
Please note that when taking an exam, it is required to use a personal Microsoft Account as work/student email address can't be used as a login credentials as per system design.
You may create a new Microsoft Account by clicking this link.
Also, please make sure that all your information on your Microsoft Certification profile is complete and has no special characters as this triggers issue during the exam registration.
If you are having the same error, you may use different browser in Incognito/InPrivate (Chrome/Mozilla/Safari). Make sure it was updated. Clear cache and cookies, check Preserve Favorites website data and check both Temporary Internet Files and Cookies then click Delete. Then allow all third party cookies through the browser settings.
In case that the issue persist, please provide us a PSR (Problem Steps Recorder) starting from doing the steps provided above until you get to the page where the error is highlighted along with the requested information through private message so we may continue troubleshooting with you.
To view your private message, refer to the image below:

Meanwhile, if you don't have an existing Microsoft Account, you may start creating your Learning profile using your personal Microsoft Account via in private browsing then follow the steps below:
1. Go to microsoft.com/learning
2. Click “Go to Certification Dashboard” (make sure that there is no account signed in)
3. Sign in using your Microsoft account/Personal Email and password.
4. On your dashboard, click “Edit your certification profile”
5. Enter your information (Note: Make sure to enter all information with red asterisk * sign)
6. Click “Save” (this will generate the MCID) then click on “Continue”.
I look forward to your response. Please note that if no response is 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.
Regards,