Admin-Images proxy timeout


I am running Omeka 3.0.3 behind apache2 proxy and all is working fine using the proxypass/proxyreserve, However when I install Admin-Images plugin and I click on the plugin it waits for the timeout and returns a proxy error as its not loading the page. All other plugins are working fine.
Also if I browse it directly on the server without reverse proxy it loads fine.
Any idea why this is happening?

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request

Reason: Error reading from remote server

AH00898: Error reading from remote server returned by /admin/admin-images/index/browse,