I try to do a One-to-One Join (Field match) in AGOL and calculate the sum. Both layers are hosted feature layers.
I get the "Unable to add feature Service Definition" error.
If I try to do a Join One-to-Many instead, it works.
If I try to do a one-to-one but as to only keep first record, it also works...
What may be causing the issues with calculating a statistic?
