That who I sent it to. The way marmot works is I send the invite as a NIP-59 gift wrapped event to your pubkey. the event was this one I believe
Then you should be able to unwrap (decrypt) that and see it contains an MLS invite message for one of you published key packages. probably this one
This is all very experimental and I'm using a new implementation of marmot called
https://github.com/marmot-protocol/marmot-ts so there might be comparability issues