I placed an elevator extremely high in the sky, around Y=250+ and upon server reboot, the server (dedicated) could not start. I do have several other mods installed.

MC: 1.20.1
Forge: 47.2.17
ElevatorMod: 1.9.1 (Modrinth)

This was the error.
[04:01:28] [Worker-Main-1/ERROR]: Async chunk load took way too long, this needs to be reported to the appropriate mod. java.util.concurrent.TimeoutException: null at java.util.concurrent.CompletableFuture.timedGet(CompletableFuture.java:1960) ~[?:?] at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2095) ~[?:?] at net.minecraft.server.level.ServerChunkCache.handler$zbo000$bailIfServerDead(ServerChunkCache.java:2122) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.server.level.ServerChunkCache.m_7587_(ServerChunkCache.java) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.Level.m_6522_(Level.java:187) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.Level.m_46865_(Level.java:4541) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraftforge.common.extensions.IForgeBlockGetter.getExistingBlockEntity(IForgeBlockGetter.java:39) ~[forge-1.20.1-47.2.17-universal.jar%23798!/:?] at xyz.vsngamer.elevatorid.blocks.ElevatorBlock.getElevatorTile(ElevatorBlock.java:302) ~[elevatorid-1.20.1-1.9.1.jar%23556!/:1.20.1-1.9.1] at xyz.vsngamer.elevatorid.blocks.ElevatorBlock.m_7753_(ElevatorBlock.java:264) ~[elevatorid-1.20.1-1.9.1.jar%23556!/:1.20.1-1.9.1] at net.minecraft.world.level.block.state.BlockBehaviour$BlockStateBase.m_60739_(BlockBehaviour.java:551) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.lighting.LightEngine.m_284404_(LightEngine.java:79) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.lighting.SkyLightEngine.m_284316_(SkyLightEngine.java:172) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.lighting.LightEngine.m_284361_(LightEngine.java:170) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.lighting.LightEngine.m_9323_(LightEngine.java:150) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.world.level.lighting.LevelLightEngine.m_9323_(LevelLightEngine.java:56) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.server.level.ThreadedLevelLightEngine.m_9366_(ThreadedLevelLightEngine.java:187) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.server.level.ThreadedLevelLightEngine.m_215156_(ThreadedLevelLightEngine.java:166) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.util.thread.ProcessorMailbox.m_18759_(ProcessorMailbox.java:91) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.util.thread.ProcessorMailbox.m_18747_(ProcessorMailbox.java:146) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at net.minecraft.util.thread.ProcessorMailbox.run(ProcessorMailbox.java:102) ~[server-1.20.1-20230612.114412-srg.jar%23793!/:?] at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1395) ~[?:?] at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373) ~[?:?] at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182) ~[?:?] at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655) ~[?:?] at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622) ~[?:?] at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165) ~[?:?]

EDIT:
Interestingly enough, this does not occur when using the 1.9 Nov 3, 23 version from curseforge.