Failed to load resource: net::ERR_FAILED

Does anybody knows what is this error that i have in chromium console for this mooc?


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I’ve found this https://stackoverflow.com/questions/23688565/failed-to-load-resource-neterr-insecure-response but it’s not the case, we don’t use ip anywhere but the domain

For example this mooc doesnot have this error

Thank you in advance