Support
Write to stebalex@gmail.com and you will get a reply from the person who made the app, usually within a few days. It helps to say which phone you are on and what you were doing at the time.
I do not have an invitation code
Then the app cannot be used, and that is deliberate rather than a fault. Baby Audio Diary is built for one family to keep a private diary; there is no public sign-up and an account without a family sees nothing. A code can only come from someone already in a family — in the app, Settings › Family › Invite someone.
I signed in but the app is empty
Signing in on its own grants no access. Enter the invitation code you were sent when the app asks for it. If you have signed in and the code screen is not appearing, sign out from that screen and back in again.
Photos will not save to my phone
Settings › Save photos and videos to my device copies every picture and video in the diary into your own photo library. It needs permission to add to your photos; if you declined that at some point, iOS and Android will not ask again, and it has to be turned back on in your device's own settings for the app.
I am not getting notifications
The app asks about notifications once, after your first entry. If that was declined, the operating system will not offer again — turn them back on in your device settings for Baby Audio Diary. In the app, Settings › Notifications shows when the device is blocking them and can take you straight there.
A recording was transcribed into the wrong language
Automatic detection struggles with short or noisy clips. In Settings › You › Dictation language, pick the language you actually speak when recording. It is set per person, so it does not affect anyone else in the family.
If a name keeps coming out mangled, Settings › Family › Name translations lets you fix how it is written in each language, and Voice corrections fixes words the transcription keeps mishearing.
Getting your data out
Settings › Export my data produces a single file with your entries, health notes, appointments and settings. Save photos and videos to my device copies the media into your own photo library. Neither needs anyone's permission but yours.
Deleting your account
Settings › Delete my account, and there is a fuller explanation here of what is removed and what happens to the diary if you are the last member of a family.
Privacy
What is stored, where it lives, and every case in which it leaves that storage is set out in the privacy policy. Baby Audio Diary is not a medical app and does not give medical advice.