As with all WLAN products, the Smart Doorbell also relies on enough bandwidth available if you want to talk to the postman. So it may be that they receive the first delivery in the morning and can answer in a fraction of a second and have to wait several seconds in the afternoon. Since it is a direct connection P2P, it is really about the bandwidth of your WLAN router. If many consumers (teenagers) are currently using the Internet, the Smart Doorbell can have difficulty establishing a connection quickly.  Some routers allow the prioritization of devices – if possible, you should do so.