As a leader it is going to happen—your team is going to hit a rough patch. Whether that is caused be internal or external forces there are some things you can and should do as a leader to keep the team empowered and confident.
First off, communication is key. Your instinct might be to sugar coat things but honesty (as usual) is the best route. The confidence and positivity needs to come from the leaders presentation of the information. Make sure to cover what happened or is happening and how it is affect the company specifically or is expected to. What decisions are being made because of the situation. And most importantly what the current plan is going forward.
Next in any situation, if it is causing the goals of the team to be compromised, that means there is a lesson to be learned. Taking some time to figure out how the team wasn’t prepared or what they could do in the future to mitigate a similar issue has the dual benefit of strengthen the team and making them feel like they are in control as they begin to work out problems and solve them.
Reshare your vision for the future. Remind your team why you are all there. Take the time to celebrate large wings but maybe more important take time out to celebrate small wins. The positivity you can generate the better—mostly people want to feel good, give them a reason to.
Maybe most importantly, keep asking your team for honest feedback on how they think things are going. Again, this will give team members control and confidence that they can exert influence of the situation.