If you received the error
Failed to create account: Data is not valid, can't create PFX certificate when trying to upload your .pfx file during the add Azure flow, it may be corrupt or password protected.
The easiest wait to test the pfx file is to run commands shown below.
To extract the private key:
openssl.exe pkcs12 -in publicAndprivate.pfx -nocerts -out privateKey.pem
To extract the certificate:
openssl.exe pkcs12 -in publicAndprivate.pfx -clcerts -nokeys -out publicCert.pem
These two commands should succeed without prompting for a password.