Unable to compute Isochrone map from layer

Good Days Nils,

I am getting an error (attached below) when trying to get the isochrone maps from layer

. May I know why I am getting this error?

The input point is taken from a layer calculated by using the ‘mean coordinate’ analysis tool in qGIS.

I am new to qGIS so please let me know if you need more clarification from me. Thank you in advance.