Webserver HTTPS diverts to router login page

MrTois

I am using a EX5501-B0 router with my Fibre connection ports have been open to run my webserver and I can access my site as normal without any problems using the standard HTTP url however when I try and visist secure page on my site using HTTPS with a valid certificate installed by myself I am diverted to my router login page.

I can access HTTPS if i use an alternative port, I have tried to change the listening port for HTTPS but this did not work.

Does anyone know why this is happeneing.