I get error SettingWithCopyWarning trying to concate two columns of a data frame in one new column

Question

I am trying to concatenate two columns of a dataframe in a new one and add it to the same data frame, but I keep getting this error:

SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.Try using .loc[row_indexer,col_indexer] = value instead.

I am trying this:

Df["concat"] = Df["Technologies"] + ";" + Df["Other Actions"]