trying to build a blueprint ug-pipe next to a buildings input:

The mod Automatic Underground Pipe Connectors (2.0.11) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event automatic-underground-pipe-connectors::on_built_entity (ID 6)
LuaEntity doesn't contain key fluidbox.
stack traceback:
[C]: in function 'index'
__automatic-underground-pipe-connectors/control.lua:217: in function <automatic-underground-pipe-connectors/control.lua:68>

Seconding this, unusable atm. Was placing a ghost pipe if that means anything

What version of Factorio?

2.1

How did you get the mod to work with that version?

I've released a new version of the mod compatible with 2.1.