Google Ads REST API: The operation is not allowed for the given context., at operations[0]
I was trying to create a campaigBudget:mutate with all information that Google Ads API ask for, but no result, they show me only one error :
The operation is not allowed for the given context., at operations[0] this screenshot may help you guys:
HEADER: 
BODY (Req & Res): 
and this is an example from Google Ads API: 
Thank you
After research I found that the problem was CUSTOMER_ID
In header we should set : login-customer-id => MANAGER_CUSTOMER_ID
and in endpoint url we should set : /customers/CUSTOMER_ID/campaignBudgets:mutate