Hi Lorena,
Due to the
recent update of policy of Customer Match, your request for mutating CrmBasedUserList will fail if the advertiser account hasn't been whitelisted for using the feature. Currently, it is not possible to test this feature against the test account. if you are facing this issue against the production account, you can contact your Google account representative to get your account whitelisted. If the account belongs to your customers, they need to contact their Google representative for whitelisting. For more information, please refer to this
blog post for more information.
Let me know if you have any further questions.
Thanks,
Milind, AdWords API Team