What causes the Content Encoding Error (Firefox) or the Cannot Decode Raw Data error (Safari)?

I have a corner case that is causing me fits. I happens only when users are on a specific VPN, and even then, only in one situation that we've found (so far).

Steps to re-create:

  1. Go to any page that has more than one entry in the Page History.
  2. Click the Tools drop-down (...) and select Page History.
  3. In the Version column, click any version except the current one.


  • In Firefox, this causes a Content Encoding Error.
  • In Safari, it causes a Cannot Decode Raw Data (NSSURL ErrorDomain: -1015) error.
  • In Chrome, it causes a 500 error.

I have googled these errors and tried every troubleshooting suggestion in the first 5 or 6 pages. I've verified our database encoding settings meet the Atlassian requirements. I've looked at headers and footers and left nav and everything else I can think of.

I suspect that it has something to do with the proxy servers that traffic is routed through when users are on that specific VPN, but I can't figure out what.

We are on Confluence 5.9.11 Server edition running on Linux/mysql.

Anyone have a thought about this? Thanks!


1 answer

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Ann Worley Atlassian Team Oct 11, 2017

I have seen issues such as you are reporting as a result of gzip compression being enabled. Please try disabling it on your instance by following the reverse of the instructions to enable it: Compressing an HTTP Response within Confluence

After disabling http compression please try again and let me know if it helps.

Thanks so much, Ann! I gave your suggestion a try and got a different error which gave me helpful information. I think our problem may be caused by a bespoke add-on. I appreciate your help!

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