If you are trying to open a .pfx file rather than a .cer file, you will need a password. In the context of R2R releases, the password is often provided in the .nfo file or the standard scene passwords (like r2r or www.r2rdownload.com — note: this varies by release ).
Select the radio button: .
Installing a foreign root certificate is . Here is why: install team r2r root certificate 2021