You’ve successfully received a SSL-certificate from GoDaddy or any other providers, and then tried to convert a crt/p7b certificate to PFX which has been required by Azure services (Application Gateway or App Service, for instance)
When you convert the cert by using the openssl you also get the following error:
You should check the .key file encoding.
Carry out the following steps: open the .key file with Visual Studio Code or Notepad++ and verify that the .key file has UTF-8 encoding. In my case, the file had UTF-8 with BOM encoding, so I saved the file with just UTF-8, and then tried the conversion again:
openssl pkcs12 -export -in cert.crt -inkey privatekey.key -out pfxname.pfx
In addition, make sure that .key file has a valid scheme:
-----BEGIN PRIVATE KEY----- Cipher here -----END PRIVATE KEY-----
Easy peasy, but troubleshooting could break you mind 🙂