Learn how to fix zipper issues like teeth not locking together, not catching or becoming loose.
As a bit of general advice, when pitching your Ensuite tent, make sure that the doors are zipped close to avoid stretching the tent too much when pegging down. This puts a lot of stress on the zipper during opening and closing.
The zipper teeth don't lock together
If the teeth on your zip are popping off, try lightly clamping down on each wing of the slider with a pair of pliers to increase the zipping pressure.
The zipper keeps catching
If your zipper is catching or the slider is not moving smoothly, try applying some lubricant to the teeth. Silicone Spray is best since it's not oil-based. If you don't have it handy, you can use a bar of soap, a candle or a Lead Pencil and run it along the zipper.