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http post - header issue?

I have a flow (several actually) where I need to take the data and post it to an external site. You can see how I have it set up here:


It posts the data to the external site but the flow itself is always marked as "failed" as you can see here:


After so many "failed" run the flow is automatically disabled which I don't want happening. What am I doing wrong? Thank you in advance for any help!


Accepted Solutions

@ExtremeLeadProg  You need to access to Windows hosting, I just created a collection in Postman and created a Custom Connector 😊.


Yes, you are right just an HTTP and it not working. You can report it to Power Automate support team.

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Super User
Super User

@ExtremeLeadProg To isolate the problem, can you please try the same request using a REST client such as PostMan or ARC.


If you get a successful response(200) in the REST client then the same should work in the Power Automate HTTP action

@CFernandes It seems to work ok in ARC: screenshot-nimbus-capture-2020.08.12-14_12_38


The specific error in flow says: Http request failed: 'The character set provided in ContentType is invalid. Cannot read content as string using an invalid character set.'.


This is what I have in there:

@CFernandes Does that bug apply here? That is talking about an "HTTP request" trigger. I am talking about an "HTTP" post action. Maybe it is all tied together somehow?


Maybe I should have posted a screenshot of the entire flow. As you can see here it is triggered by a "HTTP request" but it posts a row into a google sheet, sends a couple emails and then also posts into another system fine ( though I was able to make those work ok by using GET ) and unfortunately where I want to post this data can't use GET:



Can you please paste the details of the HTTP request in text(URL, Header, Body) so that I can try it on my tenant with the HTTP trigger.

@CFernandes Sure, thanks for checking, here you go:


Method - Post



Enter Key: Content-Type

Enter Value: application/x-www-form-urlencoded

Body: CustomFields[1]=@{triggerOutputs()['relativePathParameters']['Firstname']}&email=@{triggerOutputs()['relativePathParameters']['Email']}&CustomFields[7]=@{triggerOutputs()['relativePathParameters']['Phone']}


You can replace body with something like this just to test: CustomFields[1]=Mike&[7]=1234567890


Hopefully that is what you were looking for, thanks again.

Howdy @ExtremeLeadProg ,


Just checked with HTTP connector getting the same error.




So I decided to to create a PostMan collection(v1) exported it and tried creating a custom connector( You can refer my blog -


And then used it in the Power Automate I got a response.





The response body I get 


body {
margin: 0px;

#content {
border: 1px solid #EFECBA;
width: 300px;
height: 150px;
background-color: #FBFAE7;
top: 50%;
left: 50%;
position: absolute;

#container {
width: 100%;
height: 100%;
font: 11px tahoma;
position: absolute;
top: -75px;
left: -150px;

<div id="container">
<div id="content"><b>An error has occurred.</b><br /><br /> An error(s) has occurred while trying to subscribe you to our contact list:<br /> <br/>-You are already subscribed to list Big Home Business <br /><br /> <a href="javascript&colon;history.back()">&laquo; Go Back</a></div>


Let me know if the above helps... 


@CFernandes Unfortunately, I do not have access to Windows hosting and this seems like a lot of trouble for something that should just work?


It's just a simple HTTP post, who do we contact to get extra help? I'm new here, is there a real support channel for Flow?


EDIT: I found the support channel and submitted a ticket let's see what they say, thanks for your help so far.

@ExtremeLeadProg  You need to access to Windows hosting, I just created a collection in Postman and created a Custom Connector 😊.


Yes, you are right just an HTTP and it not working. You can report it to Power Automate support team.

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