I have my new forum installed on an subdomain which is secured through my host with a Lets encrypt cert however if I load my forums using https: they load but the minute i login on switch pages it reverts to http

I have not had this issue with other web platforms such as wordpress not sure if there is a setting i need to change or what but its rather annoying any help would be appreciated

Site in question: https://forum.andyjamison.com it loads but ends up reverting as mentioned above

 

this worked thank you had a heck of a time finding it