Error reads:
Failed to load mods: Error in assignID: item with name 'elevated-pipes--gingarou-hotel-planned-hotspring-site' does not exist.

Source: elevated-pipes--gingarou-hotel-planned-hotspring-site-fc-ns (pipe).
It suggested disabling this mod and Janus.

I reported it to Elevated pipes, they say that this mod (and Janus) are enabling a building that shouldn't be enabled for building. (i.e. they are placing the blame on the other two mods).

Hiya! I cannot reproduce with elevated pipes + flow configuration + janus. Either way with just elevated pipes and flow configuration enabled, this doesn't happen and flow configuration doesn't touch elevated pipes' entities, so this is not caused by Flow Configuration. If it's only when FC is installed, you can modify the Flow Configuration's pipe prefix denylist setting to not touch whatever entities are being created by other mods.

Thanks for the response. I'll check again, it's possible that this was fixed on their end already. It's also possible that some third/fourth mod is interacting with the others. Who knows.

Again, thanks for the response.

This should be fixed with 2.1.4, thank you for the patience :)