The app is notoriously buggy. I only use it if absolutely necessary because it’s so difficult to use. Even logging into the app gives me problems half the time. I only use it to sometimes ceck saved searches, and if I find an interesting sit I will go to my computer to formally apply. Or in the case of a recent sit that I learned about while in transit on my way to the airport, I sent a quick application message to keep my “place” in line, explaining the situation to the HO and saying I would send a more complete message as soon as I reached home the next morning. The website also has its issues, but it is far more reliable than using the app.