At times, email deliveries can take extra time to reach its recipients. Sadly many factors might be involved, some that we can't affect.
- Sending mailserver
- Receiving mailserver
- Filters like ”Greylisting” of spamfilter
- The communications between internet service providers
- Email programs like Microsoft Outlook
If you are lucky you can get the following message:
***
Delivery to the following recipients has been delayed.
This message has not been delivered yet. More tries will be done.
***
In this case you must wait and see if the delivery will be a success.
If the email is stuck in a filter and depending on what kind of filter, it takes more or less time to go through.
If the message does not reaves its destination we can check the logs if we can see what happened. Some times you must contact the receiver and see what happened on their side (mail server).