Hi @umer syed ,
If it's a problem with the Learn platform itself you'll need to reach out to their support as their team does not have an active presence on Microsoft Q&A. https://trainingsupport.microsoft.com/en-us
In regular Azure AD this can sometimes happen if there's something in place that is preventing your access, or if your identity was deleted from a directory and later restored and the restoration hasn't completed.
I would reach out to the Microsoft Learn team for support on this.