I had a user run into an error where surveys are not being submitted and are getting stuck in the outbox.
The first error occurs when trying to submit, the second error is when trying to edit/view the unsent survey.
I am able to replicate these errors on my own device. We need to get this error fixed ASAP, survey was running fine (last submission was 10/9). No changes or updates were made to the survey prior to this error (survey has been working for over a month now).
The send error with mobile device usually occurs when the network is weak or not accessible. Usually when the network is strong, this issue should not occur. Could you have the user try again with wi-fi connection and resend it from outbox to see if it's the network issue?
The user still could not send, "Still have same error. I attempted from inside city hall so wi-fi should not be an issue."
I was able to send my previous test submission even though I was originally on wi-fi as well.
I just tried another test submission (I am on wi-fi) and I got the Send Error, Survey not sent: 1
Feature service response depends on the network performance and setting. There are many possible issues related to the performace/connection issue. It could be AGOL or network but unless you have a debugged environment setup, it's hard to narrow down what caused the send failure.
As long as the feature service continue to work, your survey should be fine and just have to be patient or try othere network and mobile devices.
Please monitor the behavior and if the issue is consistent with a specific user or specfic survey, please contact our Esri Support to go over some troubleshooting to see if the feature service is still working normally.
As discussed in your other post, the issues you were having appear to be related to the update window associated with the release of 3.11. https://community.esri.com/thread/261360-why-does-it-says-2000-features#comment-961462