This KB article explains how to collect the debug logs on Android and iOS devices. Please note that the following screenshots were taken on an Android device but the same procedure is also valid for the iOS devices.
1. Open the Mobile Connect application inside your Android or iOS device and tap “Settings”.
2. Once inside the "Settings" menu, tap “Logs”.
3. Enable the “Debug Logging” setting. Before trying to reproduce the issue is recommended to clear the logs so that you only capture the fresh logs.
4. Once you have reproduced the issue, export the logs by tapping “Email Logs”.
5. Sent the logs to your email or Technical Support for further analysis.