Setting up Facebook with my Shopify store

[Malek2]

Hello,

I have a problem with the configuration of Facebook with my Shopify store, I can no longer make the connection between my Shopify stores and Facebook.
I have an error that appears telling me this sentence which I attach the screenshot :

"System users can not have duplicate names.
System users can not have duplicate names. Use another name."

I don't understand what I have duplicated !
I have checked everything, tried several times, nothing works and this problem has been going on for over a month now.

Can you help me to solve this problem please

Sincerely,