Stop Email
Because of those two reasons outlook stop to send an email and as practical outlook tells the email is still in the process of sending. an outlook user think that an email is stil sending rather actually outlook stop this email to send.
Approach to stop an email in outlook outbox which won't send
- Stop email while Packet of email is send - When email sending to Recipients in outlook it sends in small packets if you stop an email between the arrival of next packet it will stop an email to send to recipients.
- Switch off the network connection -When email is sending and seems that email won't be able to send then just remove the connection of network in computer and stop the specific email to send.
Both the approach to stop, delete or move email from outllok outbox is successful and you can use one of them as per your favour.
This can be happen always with everyone because there is no guaranty when your internet connective will get disappeared or you are trying to send a very large file on email, those both can cause stop email in outlook outbox.