OnINBOX works even behind a gateway, however, in certain cases the authentication checks done by OnINBOX may fail if the sending IP is that of the gateway instead of the original sender. To prevent this from happening, OnINBOX has built in support for Barracuda, Mimecast & Censornet gateways that you can turn on from OnINBOX Manager.

Therefore, if you are using any of the above gateways, please login to OnINBOX Manager, go to the 'Settings' page and under 'Email Gateway' select the gateway that you are using so that OnINBOX can alter the way it does its checks and be compatible.

If you are using a different gateway and OnINBOX authentication checks are failing, please contact us using the button below.