I think I found a bug in DW 9.3.2 which did not disapear when updated to DW 9.3.7 ...
It took me a while to figure out why the order notification mails did not get sent while the dynamicweb system is able to send mails.
But I found it ...
I have a cart page with a shopping cart module paragraph on it.
This paragraph is a GLOBAL ELEMENT which is used on multiple pages ... (i have a rental checkout traject and a buy checkout traject which both use the global cart paragraph)
When the order is completed the mail notifications are NOT sent when using a page with an instance of the global element.
When the order is completed the mail notifications ARE sent when using a page with the global element itself.
Here the corresponding logging (pageId: 24 has an istance of the global element)
Error: Unable to get ModuleSettings for CartV2. (pageId:24)
2017-11-16 16:37:26.1113|INFO|eCom/CartV2/Events|Order CART240: Setting currency rate to 100
2017-11-16 16:37:26.2553|INFO|eCom/CartV2/Events|Order CART240: Setting currency name to Euro
2017-11-16 16:37:38.7789|INFO|eCom/CartV2/Events|Order <No order>: CartV2 frontend visited.
2017-11-16 16:37:39.0394|INFO|eCom/CartV2/Events|Order CART240: Getting order from Context.Cart: CART240
2017-11-16 16:37:39.2809|INFO|eCom/CartV2/Events|Order CART240: Setting shop id to SHOP1
2017-11-16 16:37:39.7564|INFO|eCom/CartV2/Events|Order CART240: Previous step: 0
2017-11-16 16:37:39.9699|INFO|eCom/CartV2/Events|Order CART240: Order is not complete, next step is the first step: 0
2017-11-16 16:37:40.4864|INFO|eCom/CartV2/Events|Order CART240: Next step: 0
2017-11-16 16:37:41.8024|INFO|eCom/CartV2/Events|Order CART240: Render step: 0
2017-11-16 16:37:42.0384|INFO|eCom/CartV2/Events|Order CART240: Rendering step 0
2017-11-16 16:38:21.4399|INFO|eCom/CartV2/Events|Order <No order>: CartV2 frontend visited.
2017-11-16 16:38:21.4399|INFO|eCom/CartV2/Events|Order CART240: Getting order from Context.Cart: CART240
2017-11-16 16:38:21.8104|INFO|eCom/CartV2/Events|Order CART240: Previous step: 0
2017-11-16 16:38:21.9564|INFO|eCom/CartV2/Events|Order CART240: Getting next step from submit button: 1
2017-11-16 16:38:22.1024|INFO|eCom/CartV2/Events|Order CART240: Next step: 1
2017-11-16 16:38:22.3009|INFO|eCom/CartV2/Events|Order CART240: Saved 19 fields to the order
2017-11-16 16:38:23.9404|INFO|eCom/CartV2/Events|Order CART240: Validating order price.
2017-11-16 16:38:24.1389|INFO|eCom/CartV2/Events|Order CART240: Going to checkout logic
2017-11-16 16:38:24.2754|INFO|eCom/CartV2/Events|Order CART240: Starting checkout logic
2017-11-16 16:38:24.4150|INFO|eCom/CartV2/Events|Order CART240: Order is kept in context - getting new order id
2017-11-16 16:38:24.9147|INFO|eCom/CartV2/Events|Order ORDER44: Order is kept in context - new order id
2017-11-16 16:38:25.0650|INFO|eCom/CartV2/Events|Order ORDER44: Passing order to checkout handler: Dynamicweb.Ecommerce.Cart.DefaultCheckoutHandler
2017-11-16 16:38:28.2359|INFO|eCom/CartV2/Events|Order ORDER44: Called CheckoutDone (pageID:0)
2017-11-16 16:38:28.3874|INFO|eCom/CartV2/Events|Order ORDER44: Order is complete
2017-11-16 16:38:29.2429|INFO|eCom/CartV2/Events|Order ORDER44: Error: Unable to get ModuleSettings for CartV2. (pageId:24) See error log for details.
2017-11-16 16:38:29.5854|INFO|eCom/CartV2/Events|Order ORDER44: Redirecting to http://myproject.dev/Default.aspx?ID=24&CompletedOrderId=ORDER44&CompletedOrderSecret=**************************
2017-11-16 16:38:29.8689|INFO|eCom/CartV2/Events|Order <No order>: CartV2 frontend visited.
2017-11-16 16:38:29.9949|INFO|eCom/CartV2/Events|Order ORDER44: Removing cart from session
2017-11-16 16:38:30.2354|INFO|eCom/CartV2/Events|Order ORDER44: Getting completed order from url
2017-11-16 16:38:30.4035|INFO|eCom/CartV2/Events|Order ORDER44: Previous step: 1
2017-11-16 16:38:30.5655|INFO|eCom/CartV2/Events|Order ORDER44: Order is complete, next step is the first step after checkout: 2
2017-11-16 16:38:30.7530|INFO|eCom/CartV2/Events|Order ORDER44: Next step: 2
2017-11-16 16:38:31.0990|INFO|eCom/CartV2/Events|Order ORDER44: Render step: 2
2017-11-16 16:38:31.2890|INFO|eCom/CartV2/Events|Order ORDER44: Rendering step 2