Yah! that’s it.
I’v performed a discourse update and now my client’s discourse it’s blank page.
Source it’s there…. browser just shows a blank page.

• memory issues
  (https://meta.discourse.org/t/blank-white-page-after-update/44678)
• cloudflare cache (didn’t worked)
• set version to stable instead of test-passed on app.yml and rebuid
  (https://meta.discourse.org/t/blank-white-page-after-update/44678/13)
• remove cache before rebuild
  (https://community.bitnami.com/t/discourse-update-leaves-blank-screen/24613)
• disk space
  (https://meta.discourse.org/t/totally-blank-page-after-upgrading/45730)
• shitty plugin

Yah! Shitty plugin was my issue.
I/we are using babble – small chat plugin, lowly maintained -.
After disabling it on app.xml and rebuilt the app, it worked.