# Webdev to webdev API call failure: unable to find valid certification path to requested target

**URL:** <https://forum.inductiveautomation.com/t/webdev-to-webdev-api-call-failure-unable-to-find-valid-certification-path-to-requested-target/111521>\
**Category:** Ignition\
**Tags:** webdev\
**Created:** [October 16, 2025, 3:11pm UTC](https://forum.inductiveautomation.com/t/webdev-to-webdev-api-call-failure-unable-to-find-valid-certification-path-to-requested-target/111521 "2025-10-16T15:11:39Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [October 27, 2025, 7:20pm UTC](https://forum.inductiveautomation.com/t/webdev-to-webdev-api-call-failure-unable-to-find-valid-certification-path-to-requested-target/111521/21 "2025-10-27T19:20:18Z")

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That's not really an explanation.  
HTTP is HTTP, and `system.net.httpClient` absolutely sends well-formed HTTP POSTs if you tell it to do so (correctly). It doesn't matter that 7.9 doesn't have the HTTP **client** function, the only relevant piece is that it has a **server** , in Webdev. If you're happy, good enough, I suppose, but at this point you and/or the support rep have basically gotten lucky, not explained what was actually going wrong.

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**Author:** ![maxwell.bean](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@maxwell.bean](https://forum.inductiveautomation.com/u/maxwell.bean)\
**Post date:** [October 28, 2025, 1:48pm UTC](https://forum.inductiveautomation.com/t/webdev-to-webdev-api-call-failure-unable-to-find-valid-certification-path-to-requested-target/111521/22 "2025-10-28T13:48:38Z")

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I did get lucky. But after some further investigation I found the root of the problem. It was what @pturmel hinted at. The version was incorrect. It needed to be a http1 and not http2. I thought I set it correctly with the following code

```python
client = system.net.httpClient()
response=client.post(url,version='HTTP_1_1', params)
response.getText()

```

But I was entering the version in the wrong place, it should have been the following:

```python
client = system.net.httpClient(version='HTTP_1_1')
response=client.post(url, params)
response.getText()

```

This method and having the receiving pull the information using

> request['params']

is what created a successful connection.

It seems like 8.1 defaults to http2 type connection which makes sense since Postman will automatically identify the correct connection. I’ve learned all these things after the fact, now that I have identified the problem.

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