Hi Malcolm,

using a license server is recommended in multi server deployments. But that will not alleviate the issue that users need to login again after a failover. The issue here is that the webgateway loses the login connection to the iris instance on failover and needs to reauthenticate and reestablish. In case of a stateless application this has no user impact, but in case of a non-stateless application the user needs to reauthenticate and all data in flight is lost. 

To resolve this issue you should consider going to a multi-tier setup with appservers using ECP.   
Highlevel design:
webserver(webgateway) connects to
appserver(authenticates and serves the application)
connects to mirror via ecp

ECP is mirror aware and will failover transparently for the appservers. So users stay logged in and don't notice the failover.

Caveat: This only works if the failover is fast and happens before the appservers do any ECP operation and the ECP connection then times out.

refer to: Distributed Cluster

Hi,

a 404 error usually comes from Apache. As we don't know your Apache setup its difficult to advise. It might be that you need to add additional config to allow the new path to be accessible.
Also seeing you call this using a port number other than 80/443, i guess you are using still using PWS, which is not supported for production loads.