It says: Already running

A sleep or a breastfeed runs only once at a time for each baby. A pump runs only once at a time for each parent. You started a new one while the last one is still running. When the question names a baby, it is about that baby.

• Tap Stop and start to stop the running one now and start the new one.
• Tap Cancel to keep the running one. Nothing new is saved.

If you forgot to stop the last one, stop and start, then tap the old entry and change its end time.