Toolbox App trusts the certificates that you store in the OS system storage. 

If your environment requires you to use a self-signed proxy certificate to access Internet access or other reasons, add it to the trusted root storage in your OS.  If you have multiple certificates, add all of them to the trusted root storage.

To add a self-signed certificate to the trusted root store, use one of the following ways:

Windows

Manual

1. Double-click the certificate file to start the import wizard.
2. Select a certificate store location. This location determines who will trust the certificate – either only the current Windows user or everyone on the machine. Click Next.
3. Select Place all certificates in the following store, then click Browse, and select Trusted Root Certification Authorities. Click OK then click Next.
4. Click Finish.
5. Click OK to confirm the warning dialog.

Automated

Requires to run a terminal as administrator

certutil -addstore root <Path to your certificate>

macOS

Manual

1. Open the Keychain Access app and select either the System keychain.

2. Drag the certificate file onto the Keychain Access app.

3. If you’re asked to provide a name and password, enter the name and password for an administrator user on this computer.

4. Select a certificate from the Certificates lists, then double-click a certificate.

5. Next to Trust, click the arrow to display the trust policies for the certificate.

6. Choose the new trust settings from the pop-up menus to override the trust policies.

Automated

sudo security add-trusted-cert -d -p ssl -p basic -k /Library/Keychains/System.keychain <Path to your certificate>

Linux

Manual

1. Click Activities and open Terminal.
2. Copy the certificate file to a folder appropriate for your Linux distribution.
   

   Ubuntu or Debian 

   sudo cp <Path to your certificate> /usr/local/share/ca-certificates

   Red Hat

   sudo cp <Path to your certificate> /etc/pki/ca-trust/source/anchors

   Arch Linux

   sudo cp <Path to your certificate> /etc/ca-certificates/trust-source/anchors

3. Update the system-wide certificate store with the following command:
   

   Ubuntu and Debian 

   sudo update-ca-certificates

   Red Hat and Arch Linux 

   sudo update-ca-trust

    

4. Check the trusted certificate store after installation. Use the following command:

   trust list

   At the end of the list, you should see your certificate.