Arch Linux

Description:
Firefox can not find updates for add-ons even though they are available.
Add-ons can only be installed from https://addons.mozilla.org.


Additional info:
nss 3.17-1
nspr 4.10.7-1
ca-certificates 20140325-2
ca-certificates-utils 20140325-2
ca-certificates-mozilla 3.17-1
ca-certificates-cacert 20140824-1
firefox 31.0-1


Steps to reproduce:
1) add-on update
* have an add-on installed that requires an update
(or install an older version - e.g. for AdBlock Plus install version 2.6.3
from https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/versions/
but ANY out-of-date add-on will do)
* in Firefox, go to add-ons, Extensions tab and click Check for updates
* "No updates found" is displayed even though some add-ons that have a newer version are available
* NO ERRORS are reported to the user, no errors on stderr and no errors in the Browser Console
* Downloading add-ons directly from https://addons.mozilla.org DOES work.

2) AdBlock Plus download from developer's web site
* go to https://adblockplus.org/en/firefox
* click "Install For Firefox" and then Allow
* an error is reported: "The add-on could not be downloaded because of a connection failure on adblockplus.org."
* another error is also reported to the Browser Console:
addons.xpi WARN Download of https://addons.cdn.mozilla.net/user-media/addons/1865/adblock_plus-2.6.4-fx+an+sm+tb.xpi failed: [Exception... "Certificate issuer is not built-in." nsresult: "0x80004004 (NS_ERROR_ABORT)" location: "JS frame :: resource://gre/modules/CertUtils.jsm :: checkCert :: line 169" data: no] Stack trace: checkCert()@resource://gre/modules/CertUtils.jsm:169 < AI_onStopRequest()@resource://gre/modules/addons/XPIProvider.jsm:5306 < <file:unknown>

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Downgrading nss to version 4.10.6-1 fixes all issues.