You have to edit mide.ini and set a user and password to run the MPL so if you didn't do that it could be the reason why.
I do not have an mide.ini file, nor does running mide generate it.
Well that is certainly part of the problem ;)
You could use "install extract mide.ini /mystic" to extract it from the A44 release if it is missing.
I really need to do an update of MIDE that better supports the new theme system, python, various screen sizes as well as has some better quality of life features like auto-creating the .INI file. Its just not something people use often, so it always takes the backseat.
--- Mystic BBS v1.12 A44 2020/02/04 (Linux/64)
* Origin: Sector 7 (21:1/108)