Unable to receive m.receipt(kMXEventTypeStringReceipt) event

[AmanGupta-Stackflow]

I'm trying to get m.receipt events inside a room using the method listen(toEvents:) but they don't appear. How could I get those kind of events?
Also, I have checked my homeserver, its sending the event. I have verified on the element app as well. But i didn't able to receive on my end, Also tried various methods for getting the event i.e: getEventReceipt but still no luck.
Can anyone guide on this?