Postman Error: self signed certificate in certificate chain

Question

I try to test REST api in Postman but every time I try to POST I get the following error

Error: self signed certificate in certificate chain.

I have tried with the SSL certificate verification on and off but both methods dont work. Postman is also updated to latest v7.3.6. Tbh I dont know what to try anymore and would really appreciate any tip.

Equivoque

Try checking the validity of the certificate from online sources or through Open SSL and see if it's a valid certificate. – Custombuilt

Please refer to this link if it can help you out : blog.getpostman.com/2019/07/17/… – Allude

This question doesn't have an answer that was marked as the answer, and the original question is ambiguous. You didn't indicate whether you had setup a certificate so it's not clear how this question or answer could ever help anyone else. – Nasya

Answer 1

Go to Postman Settings > General > turn OFF SSL certificate verification

Scraggy

How to make ssl certificate verification on and make it still work? – Anaanabaena

Not really thrilled with the "turn off security and it works" approach. – Pippy

Answer 2

"make ssl certificate verification on and make it still work"

If you're under organization environment, you can:

1. Export your organization self-signed certificate as Base-64 encoded X.509 (.CER) format flat file. It could be done from Chrome.
2. Go back to Postman: Settings -> Certificates -> CA Certificates, switch on and select the file you just exported.

Crumley

I guess it is .cer (not .cre, please correct that typo) – Cornell

Also when i added this alone it is not working as well. – Cornell

Hello @rinilnath, what's the error you're encountering after applying the certificate? – Crumley

Error: error:0900006e:PEM routines:OPENSSL_internal:NO_START_LINE. This error when i added a .cer file under "client certificates" options – Cornell

As per your answer when i added a .PEM file under "CA Certificate" i get the same self signed certificate "SSL Error: Self signed certificate in certificate chain" – Cornell

Hi @rinilnath, I just checked my latest configuration again and I realized there are something different. 1. Install git and you can get file ca-bundle.crt under path C:\Program Files\Git\usr\ssl\certs or C:\Program Files\Git\mingw64\ssl\certs 2. Copy this file to a new place and maintain it by yourself. 3. Following step 1 "Export your organization self-signed certificate as Base-64 encoded X.509 (.CER) format flat file. It could be done from Chrome.", copy the Base-64 content into this ca-bundle.crt. 4. In postman CA certifictes setting, select this file. – Crumley

Answer 3

Adding CA certificates doesn't work for me. My certs are not self-signed but got the same error. Adding client certificates solved my problem. Quoted docs from Postman here: To send requests to an API that uses mutual TLS authentication, add your client certificate to Postman.

Woodworth

Answer 4

I used mkcert and here's how I managed to get rid of the error :

• On the Site Information Icon, click where it's written Connection Not Secure

• On the Connection Info dialog, click on More Information

• On Page Info, click on View Certificate

• On the Certificate tab, scroll down till where you'll see 2 links for the PEM files, and download the PEM (Chain) file

• On Postman, go to Settings -> Certificates -> CA Certificates (make sure the toggle button is ON), and specify (click on Select File) the location of your PEM Chain file.

There you are !!!

Derrek

Answer 5

My organization is using web proxy.

I had to do 3 things:

1. export the certificate
2. add the certificate it in Postman: Settings -> Certificates -> CA Certificates, enable and select exported certificate
3. disable system proxy in Postman: Settings -> Proxy -> Use system proxy, disable

You could see the proxy in console when making the call with SSL disabled

Demars