IC2 Classic - https://www.curseforge.com/minecraft/mc-mods/ic2-classic

IC2 Classic uses EU, which is supported by your mod according to the list on the curseforge page.

When I try connecting a flux plug to any type of cable, energy storage unit, or power producing object (like a solar panel), the flux plug does not receive any EU.

I have tried creating a separate network just for using EU, in case that would be a problem, but that did not fix the issue.

When testing, I also tried building out a controller and network storage, just in case the lack of storage was causing an issue, but that did not fix the problem.

I am also seeing that I am unable to connect a flux point to any IC2 Classic machine that uses EU for energy.

I heard that the ic2exp use different energy transfer method from ic2c... That makes ic2c's eu don't work with other mods