Best to follow-up early, probably via a text, especially if you notice that the email is insead.edu (usually nobody checks that frequently) or if you realise the email address is not the current company they are at (do some snooping on linkedin

)
Also, I was assigned an interviewer who actually had informed INSEAD she cannot take interviews during this period. I had to inform my AO about this..she reassigned another interviewer, but this 2nd interviewer also wasn't asked if she could do interviews for this intake! >.< Thankfully she was very nice and accommodated.
So yes, would suggest to check-in early.