It seems when this planet/mod is activated with Maraxsis and/or any planet start it crashes.

"The mod Any Planet Start (1.1.28) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event any-planet-start::on_player_created (ID 32)
The mod Maraxsis (1.31.6) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event maraxsis::on_script_trigger_effect (ID 173)
maraxsis/scripts/map-gen/maraxsis.lua:31: attempt to index local 'old_cliff' (a nil value)
stack traceback:
maraxsis/scripts/map-gen/maraxsis.lua:31: in function 'cliff_created'
maraxsis/scripts/map-gen/maraxsis.lua:102: in function '?'
maraxsis/lib/events.lua:25: in function <maraxsis/lib/events.lua:23>
stack traceback:
[C]: in function 'force_generate_chunk_requests'
any-planet-start/control.lua:116: in function <any-planet-start/control.lua:109>"

I am aware that it both mentions "any planet start" and "Maraxsis", BUT it only crashes with "Solar Halo" active.

Further more generating a new game with Solar Halo also crashes. It loads fine, but crashes on game creation, and also when trying to "circumvent" it by enabling Solar Halo after game creation.

All those combinations are working for me on the latest version (powerset of maraxis, any planet start and solar halo), both for loading a game and making a new game. Make sure everything is updated and try again. I don't touch map-gen or cliffs at all, so I wouldn't know where to start to look without more information.