Week 3 - Practice Quiz - Cannot start assigment

When I click “Start Assigment” button, I see white screen after some loading.

In developers console I found error
“Payload failed to validate against JSON schema”.
How to fix error and start assigment?

Hi @vit21ii!

Could you please try clearing your cache and cookies for the Coursera pages?

Please tell me if this works or not, so we can investigate further.

Thanks,
Lucas

I tried in new incognito Chrome window and Firefox. So, It was without cache and cookies.
It doesn’t help me.

any chance to help with this issue?
I still cannot start assignment.
I can open assignment for lesson 2 week 3, but cannot open it for lesson 1.
Also I see issue with marking lessons as completed - when I watched video, It doesn’t change icon to green (completed).