In the Campaigns section, select the campaign to pause and click the green active button to pause the campaign.  The button will turn gray and show the campaign as paused.  If you pause a campaign, all content in the campaign will automatically be paused.
To unpause or set a campaign back live, select the campaign to set active and click the gray paused button to set the campaign active.  The button will turn green and show the campaign as active.

If you have a support question or bug report, please contact our support team.