Relation x cannot be used in a find. Why?

Relation acc_standing_orders_to_acc_customers cannot be used in a find

The source and the destination for this relationship are on the same database server. Both source and destination are integers.
Any idea of what may be wrong?

when exactly do you get that?
I can’t find that text (cannot be used in a find) in our code

Not sure now, but will let you know if I see again.

I have merged a number of modules into the main solution to avoid a lot of visibility related issues. I had modules which weren’t true independent modules and they were depending on each other…

Relation is between two database connections is the only time we’ve seen this.

David is right that is the place, then yes it can’t be used, we can’t search over multiply databases at once.