Created relationship, now 400 Invalid query: Attribute not found in schema

[gleaming dune]

Errr, so I just created a one-to-many relationship, now kept refreshing and wait but I can't access the two collections. Photo is what's shown on the Cloud console.
When my site making request, they will also throw 400 error.

How can I revert this or fix this? From the collections list view, I can't select and duplicate collection from there, which I thought what I might do.

Any ideas?

[gleaming dune]

This is scary cos at least in my case here is in dev, imagine doing something like this on a production db, and it just breaks everything. Any queries to even the other unrelated collections returns 400 for my site

[gleaming dune]

So the relationship creation failed, which is completely opposite to the toast notification shown after I created it.

So, it suggested about index; so I went to check all indexes and none with the id? Anyway, deleted ALL indexes. But still 400 error 🤔