Solution:
Step1: Disable the firewall, antivirus, IP version 6.
Step2: Check the internet connection
Step3: Content drive required space. (Minimum 20 GB)
Step4: Do the Learner login.
Step5: Click on LVRD multiple times (LVRD is a refresh button present in learner dashboard)
Issue will get solved.
If issue persists, please generate the SOLAR ticket with following details.
Learner Code-(those are facing issue)
Screen shot of the issue-
Detail description.
Updated mobile number.