Yes it is.

We back issued nearly 10,000 digital badges for some 3DEXPERIENCE Certifications, so the email from Credly is so you can go and accept it. The email is intentional and legitimate, so feel free to click on the link to accept the badge if you want to accept the digital badge. We also recommend you add it to your LinkedIN profile via your Credly account.

If you didn't get am email, well then you likely didn't have the certification needed to get the badge, so no need to ask or email us as to why you didn't get an email.  

This site explains all about digital badges issued by Dassault Systemes:

https://www.3ds.com/training/digital-badges/