Documentation

Unblu 6 (latest)

Some users of Microsoft Internet Explorer or Microsoft Edge may receive the error "Network Error 0x2ef3, Could not complete the operation due to error 00002ef3."

Most modern application servers have a timeout value either equal to or greater than 75 seconds, or a more sophisticated way of handling requests where the timeout depends on their workload.

The default 'keep-alive' timeout interval for Apache Tomcat is 20 seconds. The default for the Apache HTTP Server httpd is only 5 seconds. To prevent network error 0x2ef3 from occurring, this value must be increased to at least 75 seconds.

You may choose to do so using one of the following methods:

  1. Configure the involved HTTP infrastructure (including the application server, proxies, firewall and load balancer) to set KeepAliveTimeout to 75 seconds.

  2. Configure the involved HTTP infrastructure (including the application server, proxies, firewall and load balancer) to set KeepAliveTimeout to 75 seconds depending on the user agent (only for Internet Explorer).

  3. Configure the involved HTTP infrastructure (including the application server, proxies, firewall and load balancer) to selectively turn off KeepAlive for Internet Explorer.

Failure to do so may cause a timeout, resulting in the aforementioned error.

While we have used Apache as an example here, the error is known to occur with other web servers such as Nginx, too.

Custom proxies

If you have your own proxy setup in Apache, make sure that it is a non-caching reverse proxy that does not deliver its own (cached) content. Cached content is not processed by mod_unblufilter and cannot be co-browsed.