I was told directly from tinie that these mag 500 series boxes are not guarantied to work on papiao services. It started with the Minstra middleware, which replaced the original Stalker Middleware.
Stalker was originally based in the mag 250 models and the 254 models, which is why setting that compatibility mode set to the 254 had helped in the past, sometimes set as mag 322 as well.
There are some Mag 500 series models that do have that compatibility option and some don't. You'll find all those that don't will not work no matter what is tried.
The STB emulator is the same way, It's based on the Stalker on a mag 250 OS
This Minstra was introduced maybe 5 years ago and has been from the start a troublesome format for papiao and other private servers.
If any remember, Infomir which is the Mag manufacturer, tried blocking Mag receivers from connecting to private servers. A private coder from online figured out a way around that and released a 'modified' file for those being blocked and that was before infomir even had made the change to Ministra middleware (which is their iptv program).
I still have that 'modified' file on my mag254 model.
Moral of the story. Mags are not the best devices for a private server, nor can they be trusted to be.
They originally are designed for a campus type atmosphere, or business or communications and that type of things