The server crashes unless the "Skyroot beds" and "Enable colored beds" config options are both enabled. Disabling either of those two options (or disabling both of them) crashes the server.

I've tested this with Forge 14.23.5.2768 and with Forge 14.23.5.2854. In both cases, I used The Aether v1.4.4 and Aether Continuation v1.2.3, with no other mods installed.

Some crash reports

Forge 14.23.5.2768, "Skyroot beds" and "Enable colored beds" config options both disabled: crash-2020-06-24_20.21.40-server.txt
Forge 14.23.5.2768, "Skyroot beds" option enabled and "Enable colored beds" option disabled: crash-2020-06-24_20.23.26-server.txt
Forge 14.23.5.2768, "Skyroot beds" option disabled and "Enable colored beds" option enabled: crash-2020-06-24_20.22.26-server.txt

Forge 14.23.5.2854, "Skyroot beds" and "Enable colored beds" config options both disabled: crash-2020-06-24_20.30.00-server.txt
Forge 14.23.5.2854, "Skyroot beds" option enabled and "Enable colored beds" option disabled: crash-2020-06-24_20.31.29-server.txt
Forge 14.23.5.2854, "Skyroot beds" option disabled and "Enable colored beds" option enabled: crash-2020-06-24_20.30.45-server.txt

Skyroot beds removed in the latest version of this mod, making this issue void