Issue Summary

This is reproducible on Data Center: yes

When a large number of users is exported, the export fails to generate

Steps to Reproduce

1. Open an Audience specific page with at least 11500 users
2. Go to Audience >> select "Options" >> Export all users

Expected Results

All users are successfully exported

Actual Results

The export gets 'stuck' and though it initially says it's complete, the download is never made available. Upon revisiting the page later, it says "Your export is taking longer than expected, but it’s still in progress. Return to this page later to see when your export is complete." but it is never completed. 

Workaround

Use the API to export the users