To avoid a browser warning when using HTTPs or for the green check in Adobe Reader you need to install the StepOver Root Certificate.
Download of the Root Certificates. The required depends on the manufacture of your device, if you are unsure about this you can find the manufacture information on the info page of your device.
StepOver GmbH
https://www.stepoverinfo.net/download.php?file=HWRootCertificateStepOverEuropa4096.zip
StepOver International GmbH
https://www.stepoverinfo.net/download.php?file=HWRootCertificateStepOverInternational4096.zip
Extract the Zip file on your system and open the location with the Finder
Double click HWRootCertificateStepOverEuropa4096.cer (or HWRootCertificateStepOverInternational4096.der by the International)
Confirm the installation with your Login
You will see the StepOver (International) Hardware Root CA (4096) inside your certificate list
Next you need to right click on the certificate and select to check the it.
A new window with information about the certificate will popup. Extend the trust option
You need the certificate to be trusted with the first option
Confirm this change with your login and repeat the same for the second certificate by double clicking on the HWRootCertificateStepOverEuropa4096Intermediate.cer (or HWRootCertificateStepOverInternational4096Intermediate.cer)
After you installed both certificates and set them to be trusted you should see them inside your certificate list
With the installation in your personal certificate store, your browser should already open the https Version of the device website without any warning.
If you want that Adobe Reader shows a green check of the signature instead of the yellow warning, you need to import the certificates also inside the Reader.
For that open the Settings
Select the categorie “Signatures” and select there the Identity and trusted certificates
Select on the left side the trusted certifcate, next click on “import”. In the new window you need to click on “Browse…”
Select now HWRootCertificateStepOverEuropa4096.cer (HWRootCertificateStepOverInternational4096.cer) and repeat the same for the HWRootCertificateStepOverEuropa4096Intermediate.cer (HWRootCertificateStepOverInternational4096Intermediate.cer)
You should have now both certificates inside your list
Select in the top list one of the certificates and then select it in the upper list again. Next click on “Trust…”
In the new Window you need to enable the checkbox “Use this certificate as trusted root” and confirm it with OK
Repeat the same with the other certificate and finish the certifcate import with button “Import”
You should get the confirmation that both certificate were imported
Confirm this message and close the other window.
Your Adobe Reader should now show a green check