Can you please make sure you have auto upload turned on in the app’s settings? If so, please post a screenshot of the error message you’re getting and send log files from the app to help@inaturalist.org.
Here are instructions for how to take a screenshot on several types of devices: https://www.take-a-screenshot.org
To send log files, go to the About tab in the app and tap three times on the version number. You will then have the option to email the log files to us.