Can't get a streak

So I've been trying to get a streak with 1 of my friends for awhile now but no matter how much we try it doesn't work I can't send a streak pet invite or anything. However the weird thing that I've not seen explained anywhere is I can get one with other people and so can she so yeah I'm really confused if anyone can give me a explanation/solution I'd appreciate it greatly thank you.

I'm exhausted so sorry if this is bad grammar 😭