Sharepoint List function not working on another Sharepoint

Hello everyone 🙂 

I Am having an issue with a SharePoint of mine. 

On my Test SharePoint, the function is working fine, but on my production SharePoint I get a syntax error.

Here is my code : 
=STXT([Scan Envoi];12;12)&" / Retour : "&STXT([Scan Retour];12;12)

Basically what it does is : 
I have my collegue from the warehouse scanning labels for Purolator. They scan 34 characters but we only need the 12 in the middle. So I made this code to keep the 12 in the midle then write : " / Retour :" (return) and then the function again to return the 12 characters only. 

It function on my test SharePoint but on my production SharePoint NOPE.

It's not a problem with the column cause I tried using one that were already created or create a new one. Still the problem is still there. Tried with a different account, same thing 😕

I'm really lost at this time. Why it would work on a Sharepoint but not another one ?