I am using QGIS version 3.8.3-Zanzibar
I have a .shp file and I want to compute the area by using Vector/Geometry tool/Add Geometry attributes.

Runnig this tool I get :

*Feature (11) has invalid geometry. Please fix the geometry or change the Processing setting to the "Ignore invalid input features" option.
Execution failed after 0.06 seconds*

Any suggestion how to solve this?
Thank you