On the customer center, we go to a Sales Order, we click on it and we receive the following message. Any idea what it could be ?

The Customer Center role appears to be missing a permission. Does your sales order link to fields custom tables or fields that may not have permission. NetSuite is quite smart/strict on what standard records can be displayed through the centers

That is really weird message to me, seems like a direct one (and a little custom to me). I am expecting netsuite would have provided the message like , you don't have the permission for xyz . Get the permission and try again.