Mobile app - leave reason

Hi, my employee is having issues submitting leave because the leave reason is missing. She is able to do so last month, but now that she's trying to apply leave again, there's nothing in the leave reason section. Nothing has changed in the back end - her leave entitlements are still there in her profile. It's just strange that she could do it last month, and now having trouble again. She's quit the app and restarted many times. Please advise.