Failed Mckinsey R2. Going forward

Hi,

I failed Mckisney R2 on the casing which was mediocre on both interviews and that was the reason for them to not extend an offer. I was not given a ban on reapplying or was not explicitly told one at least and they said that i could reply later if i wanted.

So my question to you is, when is it prudent to reapply? Can I reapply as of now directly or am i blacklisted and wont qualify for an interview again?