When it comes to sending messages to guests' email addresses, AirHost can only confirm receipt up to the response from the recipient's mail server.

It's common for messages to be delivered to the spam folder, even in services like Gmail. However, carrier emails often have robust spam filters in place. These filters are activated by default and protect the device without requiring any user settings. It's often the case that filtered messages cannot be seen in the device's folders. Even in such cases, since the mail server confirms receipt, it appears as a successful transmission from AirHost's perspective.

Unfortunately, it's not possible to request guests to set permission to receive automatic messages before they are sent, so there will inevitably be instances where messages are not delivered. In such cases, alternative follow-ups through phone calls, SMS, or direct interactions at the location may be necessary.