0x80070057Invalid data has been used to update the list item. The field you are trying to update may be read only. In SharePoint

<nativehr>0x80070057</nativehr><nativestack></nativestack>Invalid data has been used to update the list item. The field you are trying to update may be read only. in SharePoint

Solution:-
Item["Title"] = "Test";

don't use Item["LinkTitle"]. this is readonly field.

Thank You.