Add a new Column in Power Query

Hi, this is my problem

I have 2 Tables "Ventas" and "Reuniones", and my goal is add a column (N° Reunion) in Ventas, i try with Merge Queries, the matching Column beetwen the 2 Tables is "Fecha", the parameter is unique in "Reuniones" and various in "Ventas", but the result at Expand the Merge Queries is only "null",

what it´s wrong? or exist another form to do that?

Regards