Error 3734

[LEO DEL CIELLO]

I am a beginner in MySql though I have some experience with dbs (Sql Server).
I am trying to forward - engineer a diagram which includes 2 tables and a relation between them .
I have generated the relation using the environment tool, specifying the PKs of both tables as usual.
I keep having a 3734 error on a column which is part of the PK of one of these tables.
The error states :
"ERROR: Error 3734: Failed to add the foreign key constraint. Missing column 'IdArticolo' for constraint 'fk_Azienda_has_Articolo_Articolo1' in the referenced table 'articolo'"

Where 'Articolo' and 'Azienda' are the two tables , and 'IdArticolo' is one of the columns which are part of Articolo's PK. The column does indeed exist, and it is written exactly as the error states (I mean no mismatch in capitalizing), but for some strange reason it cannot find it. What could be the cause ?