Missing field 'id' (in 'itemListElement.item')

This post describes how to fix the error Missing field 'id' (in 'itemListElement.item') which can occur in Google Search Console. Cause This error can occur when the optional field 'id' is missing from item in breadcrumb structured data. You can use Google's  Rich Results Test  to verify this issue: Resolution To resolve this error, add the itemid attribute to the item in the breadcrumb structured data, as highlighted below. < ol   class ="css-breadcrumb-trail"   itemscope   itemtype ="http://schema.org/BreadcrumbList">      < li   id ="breadcrumbTrail_listitem1"   itemprop ="itemListElement"   itemscope =""   itemtype ="http://schema.org/ListItem">          < span >              < a   id ="breadcrumbTrail_crumb1a"   itemscope =""   itemtype ="http://schema.org/WebPage"   itempro...