HTTP POST failed - BadRequest, ConnectionFailure - Same URI does work in browser

[J-WVanDerLinden]

I'm trying to do a POST to an API using the HTTP action. I've successfully tested the URI using Postman, it uses only query parameters, no headers or seperate verification (key is also in the parameters).

The HTTP action returns an error: BadRequest - ConnectionFailure, Unable to connect to the remote server.

Being inexperienced in API calls, this is what I thought to try:

• Simplifying the HTTP action by putting all the parameters in the URI. Now the URI field is the only filled field.
• Pasting that URI into the browser. This gives a valid response, which is really puzzling to me. What could be the difference here?
• Making a custom connector. This also gives a valid response. Unfortunately I'll eventually need to use some functionality the connectors don't support, so I'll need to use the HTTP action.

Does anyone know how to debug this further? And what could cause the HTTP action to fail while the browser and custom connector succeed with the same URI?

Edit:

I have copied the Flow several times without changing anything. Now some of these flows consistently work and some consistently don't. My best guess is that each Flow uses its own IP address and some of those are blocked by the receiving API. If anyone can confirm this it would be appreciated.

[ManishJain]

Hi @J-WVanDerLinden ,

Are you sure you are doing POST call with query parameters ? Does it require you to authenticate first and get bearer token ?

Thanks

[J-WVanDerLinden]

Yes, I am definitely doing a POST call with parameters. The authentication key is one of the parameters. This is not best practice, but hey, it's not my API 😉

[ManishJain]

Hi @J-WVanDerLinden ,

Can you please share screenshot of flow and Postman to help you better , please remove token value .

Thanks

[J-WVanDerLinden]

Hi @ManishJain, 

Thanks for replying! 

Here's the Flow:

In the meantime I have copied the Flow several times without changing anything. Now some of these flows consistently work and some consistently don't. My best guess is that each Flow uses its own IP address and some of those are blocked by the receiving API. Would you say that the only explanation? Or the most likely reason?

[ManishJain]

Hi @J-WVanDerLinden ,

The API key that you are using is the cause for this. If this still holds good it will work otherwise it wont and I believe there is nothing stopping based on IP . 

Thanks

[J-WVanDerLinden]

Hi @ManishJain,

I don't think it is possible that the API key is the cause. As I have used the same API key in both Flows and one Flow does work consistently.

I have asked the owner and the host of the API to check incoming connections and whether they're blocked.