Postman CA certificate not found [Ubuntu][Snap]

I’ve followed the instructions to setup the HTTPS proxy on Postman on Linux (Ubuntu). However, when I try to copy the certificate from the Postman’s configuration folder:

sudo cp ~/.config/Postman/proxy/postman-proxy-ca.crt /usr/share/ca-certificates/extra/postman-proxy-ca.crt

it fails with the following message:

cp: cannot stat '/home/<my_user>/.config/Postman/proxy/postman-proxy-ca.crt': No such file or directory

How can I setup the proxy properly?


  • Ubuntu 21.10
  • Postman Version 8.12.5 linux 5.13.0-22-generic / x64
  • Snap version

Facing the same problem here Attactin the screenshot as well please help here its a blocker

Hi there. I had the same issue on Ubuntu 22.04 LTS and resolved it by following these steps. hope this demonstration help you solve the problem. here is my system information:
ali@ali-GE620DX:~$ uname -a
Linux ali-GE620DX 5.18.10-051810-generic #202207071639 SMP PREEMPT_DYNAMIC Thu Jul 7 17:34:42 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

  1. I have used the non-containerized version of Postman due to this fact that Snap version of Postman have some limitations (Capture Request and cookies via Interceptors for example.)

  2. Download the latest version of Postman binaries: (non-containerized)
    Download Postman | Get Started for Free
    My Version was:

  3. Unrar the compressed file somewhere in your storage.

  4. Open the Postman App and launch a “Capture Requests session”. After doing that the certificate file should be located at the following location: (Note: Change the segment “Ali” with your username)

I bet you don’t see these files! ok, then you can check the Log files generated by the Postman app. These files are located in: (Note: Change the segment “Ali” with your username)


  1. if you have such a message in log files (proxy_node_process_prod-node-process.log or main.log) continue the forehead steps:

    RSA PRIVATE KEY not found from openssl output:\n—stdout—\n-----BEGIN PRIVATE KEY—…
    Most likely it is related to the “pem” dependency of the postman app and this open issue on Github:
    OpenSSL v3 support · Issue #316 · Dexus/pem · GitHub

  2. This is a temporary solution until the above issue ll be close.
    make a backup of pem.js file:

  3. Change the original file like this and save the file:
    (Here is my pem.js file after the new changes: Ubuntu Pastebin)

    var RSA_KEY_START = ‘-----BEGIN PRIVATE KEY-----’
    var RSA_KEY_END = ‘-----END PRIVATE KEY-----’

    openssl.exec(params, ‘PRIVATE KEY’, function (sslErr, key) {
    function done (err) {
    if (err) {
    return callback(err)
    callback(null, {
    key: key

  4. After doing that close the Capture Session and the Postman app, then delete the "proxy " folder located at:

  5. One again lunch the post man and Capturing session. This time you should have two new files here: /home/ali/.config/Postman/proxy/

  6. That is perhaps what you want. you can continue to move the certificate to the client device and trust it there and then enjoy the “Captured Request”:

Thanks, Ali.