HTTP Activity(POST method) not working properly

Hello Buddies,

I am using HTTP POST method on my workflow, also passed parameters in the body string and headers collections. I am getting 504 error but it is perfectly working on my power automate flow. I want to know any other restrictions for headers value(like characters limitation) which we pass

I also noticed when I pass headers value in the properties panel with the help of variables and when I click the configure button on the HTTP activity the same argument is displayed as “1.32: VisualBasicValue” , attached SS for your reference. Don’t know whether this error is because of this is issue. please help me out to solve this issue.


Hi @Jeeva_Natarajan

About the first issue, I would advise you to try sending the same request from something like Postman and from Studio to a site like
Naturally, don’t include any real credentials, but it should give you an idea how the two POST requests differ and what could be the issue.

As to the second issue, it is a known bug and will be fixed in the future.

Hi @Jeeva_Natarajan

Here are some things you can try to troubleshoot the issue:

  1. Check the request and response: Use the “Log Message” activity to log the request and response for the HTTP POST method, and compare them with the request and response in your Power Automate flow. This can help you identify any differences that may be causing the 504 error.
  2. Check the URL and parameters: Make sure that the URL and parameters of the HTTP POST request are correct and valid. You can also try using a tool like Fiddler or Postman to test the request and see if there are any issues with the URL or parameters.
  3. Check for server errors: The 504 error could be caused by an issue with the server or network infrastructure. You can check the server logs or contact your network administrator to see if there are any known issues that could be causing the error.
  4. Check the headers value: As you mentioned, there could be a problem with the headers value that you are passing. While there is no specific character limit for the headers value, it is possible that the value is too long or contains invalid characters that are causing the error. You can try reducing the length of the value or removing any invalid characters to see if this resolves the issue.


Just to close the topic. The WebApi 1.18.0 fixes this issue.