Open the queue of outgoing campaigns (Delivery > Queue).

There are three menue items:

• Prepared campaigns with the campaigns waiting in line
• In delivery with all campaigns which are currently sent out
• Network campaigns with all network campaigns (special feature)

Campaigns in the queue can be stopped by clicking Cancel delivery up to 5 minutes before start of delivery:

After a short while the campaign is not visible in the queue anymore but will be seen in the drafts. The assigned (static) target group that has been will receive the prefix “CANCEL_” and will be moved back to the address lists. The cancelation will be listed in the campaign’s logfile. [2019-07-04 17:04] delivery cancelled by xy / promio.net GmbH

Also running deliveries (type: default) can be canceled or paused. This does not count for A/B tests and network campaigns.