I need .pfx file to install https on website on IIS.
I have two separate files: certificate (.cer or pem) and private key (.crt) but IIS accepts only .pfx files.
I obviously installed certificate and it is available in certificate manager (mmc) but when I select Certificate Export Wizard I cannot select PFX format (it's greyed out)
Are there any tools to do that or C# examples of doing that programtically?
If you're looking for a Windows GUI, check out DigiCert. I just used this and it was fairly simple.
Under the SSL tab, I first Imported the Certificate. Then once I selected the Certificate I was able to export as a PFX, both with and without a keyfile.
https://www.digicert.com/util
Although it is probably easiest to generate a new CSR using IIS (like @rainabba said), assuming you have the intermediate certificates there are some online converters out there - for instance: https://www.sslshopper.com/ssl-converter.html
This will allow you to create a PFX from your certificate and private key without having to install another program.