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Regular Visitor

Call to web service allways return 401, no detect custom headers

Hello everyone, I am trying to execute a call to an API of a web service and it always returns the 401 error and the problem is that it does not detect the custom headers that I put, I only have to send one and I am writing it the box of custom param in mode key:value and the service must return a 201 with a location, the same call withc Postman for example return 201 CREATED with the headers result.




Has anyone had this problem?





Super User
Super User

Hi @javier-raneros 


Instead of the words key and value I guess you need to send the actual key and the actual value.

Also see in postman if the custom headers are in any particular format.

Is it something like below with quotes where test is the key and true is the value?

test: 'true' 


Give a minute to this video and you will get some pointers

Set Custom Headers on an API Request in Postman |


Responsive Resident
Responsive Resident

If your authentication is using bearer just put this in the header



Authorization: Bearer <token>



If using basic authentication


Authorization: Basic ZGVtbzpwQDU1dzByZA==

Regular Visitor

Good morning, thanks for the interest and sorry for delay (i'm out off..)


In this first request it is not necessary to authenticate, first a value is passed in the header so that it returns a Location and then with that value in another request to authenticate in that Location.

But my problem is that I don't know how to fill in the fields of the request in PowerAutomate; in Postman it works correctly and returns OK 201 but from PowerAutomate it returns 401 as I enter the data.


Call from PowerAutomateCall from PowerAutomate


Call from PostmanCall from Postman


In the case of Postman I enter them in the Headers fields because it indicates it and in PowerAutomate in the Custom Headers field. I have tried all the combinations: with single, double quotes, without them, etc and it always returns 401 that this Header is missing.


How to pass this data?


Very very thanks,

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