Error: exec proxy not found for :: AdMob :: showAd

[dinesh-tawar]

I am getting below error for cordova-plugin-admob-free in ionic application
Error: exec proxy not found for :: AdMob :: showAd
tab1.page.ts:34 PROBLEM LOADING BANNER: Missing Command Error

I did further investigation, In cordova.js, the internal map of proxy function var CommandProxyMap = {};
does not have an entry of 'AdMob' because this proxy object is null and throws the above error.
get: function (service, action) {
return (CommandProxyMap[service] ? CommandProxyMap[service][action] : null);
}

I will appreciate any help on this.
Thanks!