The mod Iridescent Industry (0.8.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event IridescentIndustry::on_tick (ID 0)
IridescentIndustry/control.lua:237: attempt to index local 'e' (a nil value)
stack traceback:
IridescentIndustry/control.lua:237: in function 'update_entity_for_azure'
IridescentIndustry/control.lua:373: in function <IridescentIndustry/control.lua:274>

caused by doing blue circuits from azure on fulgora - recipe got removed? After machines removal it stopped to crash server

running /ii_fix_azure fixed this for me

Unfortunately, I'm not able to reproduce this. For 0.8.2 I tried to make the scripting generally more robust and print out an error message to the screen rather than unceremoniously crashing, so it should be more playable while I continue to look into it.