I have a private AWS server. I have a customer who uses power app to create rest api calls to fme server installed on this server. They need the server to be at a security level of https. They access fme server using the URL of the server through a gateway with an enabled port.

Aws has its own security certificate but it charges a lot of money for a private CA. There are free websites out there but they want the domain registered. I can't register the domain of the AWS as it's a private server

I went through the safe http to https tutorial using a self signed cert (pfx) section. However, while I managed to get the fme server to use https an untrusted error comes up, even if I add the cert to trusted certificates. I suspect it's because it is a self signed cert. I've had to roll back fme server to http as the users couldn't access the rest API anymore.

This is my first dabble with security certificates but I can't see a solution around this.

thanks for any advice