Some Lessons in Elastic Observability could't open

I recently logged on to review Observability Fundamentlas (1 year access)
There are four sessions in total, but two sessions are not connected.
Lesson 1 and 2 is not opened. The page shows only "Your course is loading" message.
But Lesson 3 and 4 are well opened.
How can I access the Lessons 1 and 2?

Hello @jongpil.won ,

Are you still having this issue?

I tried to replicate it on my side and I can correctly open the four lessons.