We have found that the most recent version of Miniforge - 23.11 - does not succeed in installing MFiX, I believe there is an issue with custom channels. We have changed the “Download Miniforge” links on the MFiX installation page to point to version 23.3.1-1 which is known to work (thanks to @ZJUlin for the tip). All users who are having difficulty installing MFiX are encouraged to revert Miniforge to 23.3.1 and try again.