Normally your system maintainer will provide a copy of the application certificate which you can then add to your browser's certificate store. However, if necessary you can download a copy of the certificate using Chrome.
Login to COM.
Press Ctrl+Shift+I.
From the panel on the right select Security. If necessary click on the >> icon to select Security.
Click on View certificate. The certificate is displayed.
Click on Details.
Select Copy to File.
Click Next.
Select DER encoded binary X.509 (.CER) and click Next.
Enter the path where to save the file and the file name. This can be done using the Browse button.