You can get a jump start by creating a log file during submission. See Troubleshoot—Survey123 for ArcGIS | ArcGIS - you don't necessarily need an AppStudio console; turning on logging without a console selected (or the 'searching for consoles' circle still showing) will log to a file. Turn on logging and attempt to submit the data. Then you will need to retrieve the log file:
- Windows: C:\Users\<username>\ArcGIS\AppStudio\logs
- Mac: ~/ArcGIS/AppStudio\logs
- Android: /ArcGIS/AppStudio/logs
- iOS: Connect the device to a computer with iTunes. In iTunes, click on the device's icon and then Click on File Sharing (used to be Apps) no the sidebar. From the list of apps, select Survey123 (this is the second list if you have 2 list of apps). Select the 'ArcGIS' folder that appears in the list of files to the right. Click 'Save to...' to export the folder. You will then find the log file in ArcGIS/AppStudio/logs. This is also the procedure to try to submit teh data from another device; see Troubleshoot—Survey123 for ArcGIS | ArcGIS
The log file should have the submission error towards the bottom of the file; depending on the exact error, there might be a more detailed message that explains what the issue is.