Error run RFmerge with my data

[martaddi]

I followed the tutorial and tried to run with my own data. Everything seems to run well but the RFmerge function gave this error.
Please i need help to fix this error.

Error in if (!sf::st_is(mask, c("POLYGON", "MULTIPOLYGON"))) { :
the condition has length > 1

[fmanquehual]

In my case, it was because my basin mask had two polygons and not one.