I have created an App in AEM 6.1 (SP1). I have completed the full cycle in my local from creating the App Template/Components, Connecting with AEM Mobile, Uploading Article, Uploading Shared resources etc. All works fine from my local but when I deployed my code in one of our test environments and tried the same thing I am getting following error when Uploading Shared Resources and images from DAM aren't showing in Preflight.
Upload Shared HTML Resources FAILURES: Failed Shared HTML Resource Upload
Can you look at the AEM error.log and see if there is anything there? AEM should log the problem at some level. If you could provide a screen shot of the error in the log it would help
Also, can you tell us how big the HTML Resources file is? Info on the number of individual files in that resources file would help as well (I believe MODs has a limit to the number of files in a single MODs entity).
You can get the resource file from a URL (see below):