I know by title it feels not acceptable but here me out. I have registered an below event in my cmp file

<aura:registerEvent name="showToast" type="force:showToast" />

and an helper method as

showToast : function(component, title, message, type) {
        var toastEvent = $A.get("e.force:showToast");
        toastEvent.setParams({
            "title": title,
            "message": message, 
            "type": type,
            "mode": "sticky",
            "duration": "50000"
        });
        toastEvent.fire();
    }, 

and i am calling this method on success callback of xyz functionality as

helper.showToast("",'SUCCESS', 'The Document has been Removed', "success");

but I see nothing on the page. It's a lightning page only.

I have even tried to give more duration so that I can inspect if it is there in the DOM or not but no I can not see.

I have checked SLDS.css, it's loading properly, I have event kept toast css classes in concerned component style also but to no avail.

Could you please provide some more directions on how to debug this to resolution.

Thanks, Akash