Hi, i’ve installed openproject-ce on CentOS Linux 6.5
All seem to work fine, but when openproject send an email i got a proxy error although the mail arrived.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /admin/test_email.

Reason: Error reading from remote server

Apache/2.2.15 (CentOS) Server at

i cannot figure out what happen reading logs
production log:

Started GET "/admin/test_email" for 151.xxx.xxx.xxx at 2015-01-20 11:14:02 +0100
Processing by AdminController#test_email as HTML
  Rendered user_mailer/test_mail.html.erb within layouts/user_mailer (0.6ms)
  Rendered user_mailer/test_mail.text.erb within layouts/user_mailer (0.4ms)
Connecting to database specified by DATABASE_URL
Creating scope :open. Overwriting existing method WorkPackage.open.
Creating scope :like. Overwriting existing method Principal.like.
Creating scope :open. Overwriting existing method Version.open.
Creating scope :public. Overwriting existing method Project.public.
Creating scope :visible. Overwriting existing method TimeEntry.visible.
Creating scope :givable. Overwriting existing method Role.givable.

httpd error log:

[Tue Jan 20 11:14:18 2015] [error] [client 151.xxx.xxx.xxx] (20014)Internal error: proxy: error reading status line from remote server 127.0.0.1, referer: http://95.xxx.xxx.xxx/settings?tab=notifications
[Tue Jan 20 11:14:18 2015] [error] [client 151.xxx.xxx.xxx] proxy: Error reading from remote server returned by /admin/test_email, referer: http://95.xxx.xxx.xxx/settings?tab=notifications

I’ve increased proxy timeouts

ProxyPass / http://127.0.0.1:6000/ retry=0 acquire=3000 timeout=600 Keepalive=On
ProxyPassReverse / http://127.0.0.1:6000/

on conf.d/openproject-ce.conf, and

export WEB_TIMEOUT=150

on conf.d/other

without success.
This happen even i configure sendmail or gmail, the mail arrive but i got the error.
Even when i try to perform operations with notification, such the creation of work packages, it’s fail unless i unckeck notifications.
Have anyone experienced and solved this issue? Thanks.