Standalone maps bug in 1.56 fixed
Following the release of versions 1.56 of ATS and ETS 2 by SCS, a major bug has been identified: when creating a new profile, it was no longer possible to select the map module corresponding to a standalone map. The bug has been fixed in latest release. You have to download update in Steam.
SCS broke standalone maps in 1.56
Following the release of versions 1.56 of ATS and ETS 2 by SCS, a major bug has been identified: when creating a new profile, it is no longer possible to select the map module corresponding to a standalone map.
This makes it completely impossible to start a new game on certain standalone maps.

Affected only new profile creation, so if someone have already been created profile on standalone module it will work so it can be only replaced old version of mod with the new one in the mod manager.
We still do not know if it is just bug or the feature has been removed from the game and all standalone maps (count of which not very big) are become inacceptable for new players. The issue is already reported top SCS and there are topics on SCS Software forum.