You will get this error when your adsense account has been suspended or disabled.

if your Google adsense disabled or suspended then your admob will get this type of error.

so you should try by using new email id or you should wait untill your adsense active if it is suspended for 30 days or whatever mail you got from Adsense team.

I think it may help may . if you have any other query comment below.

thanks