SalesForce Integration

We are in the process of integrating Salesforce and Mautic, we can connect and see the fields to map. However, there are a data custom object fields (especially lookups and master detail relationship fields) from salesforce that aren’t available does anyone know how or why this is and what is need to be done to pull these through with the rest of the fields.

We are in the process of integrating Salesforce and Mautic, we can connect and see the fields to map. However, there are a data custom object fields (especially lookups and master detail relationship fields) from salesforce that aren’t available does anyone know how or why this is and what is need to be done to pull these through with the rest of the fields.

Can anyone help in this regard please