i had the same problem and i fixed it, here's how: use a different browser ( i switched from Chrome to Firefox in order to download the file ) after downloading the file, add the extension (.pdf) to the file and you will get your certification 🙂
Firstly, congrats on becoming certified! Secondly, can you send me the link you are trying to access the certification with? Once I have that I can take a look and see if we can get this fixed for you.
Thanks for reaching out. What happens when you try to download the certificate? Which certification is this for? What email did you take the certification on?
Once I have more information I can help troubleshoot this.