When connecting to Linchpin Mobile Gateway the 'Internal request' connection test fails due to an error.
If this check fails the system is not able to perform http requests to its own address. In most cases this is caused by the network configuration.
In many cases Confluence uses a gateway to perform http requests. This gateway was not able to access the Confluence server and returned a 404 http status code.
The network configuration must be adjusted so that Confluence can reach itself via http requests.