I know that this is an older issue but just came across it today. I have several in the field and they are able to open the survey and fill the form out, but they are unable to send it. I have checked permissions and also have had them log out and log back in and neither worked. I had them log out and logged myself in on their devices and was then able to send the items. I am a site administrator but not the author of the survey only the author of the survey and myself are able to submit forms. I have checked permissions multiple times, each users role and share the survey publically. Not sure what to do next?