Hi @Shadab_Ali and welcome, we are delighted to have you here!
Thanks for asking the HubSpot Community!
Did you try the “HubSpot CMS Certification: HubSpot CMS for Developers Certification Course (FREE Certification Course)”?
Where exactly do you see a blank screen?
For which course did you enroll?
Did you try in an incognito browser?
The more info, screenshots (without sensitive/confidential information), and details you can provide, the better the Community can assist.
Thanks and have a great weekend!
Bérangère