In Single Player, when claiming and force loading a chunk it does not work across dimensions. For example, my Refined Storage system is in the overworld, but when entering the nether I can not connect when using a dimensional card. I have tried opening to LAN, and even changing the serverconfig in the ftbchunks-world.snbt file to ALWAYS instead of Default, as well as granting my user the ftbchunks.chunk_load_offline permission in game.

It appears the force load does not work anywhere, I went 10k blocks away in the overworld and it doesnt work once the chunks are unloaded

This was actually the interaction between the Advanced Wireless Antenna and the one belonging to refined storage. If you change one belonging to Refined Storage it works correctly. This is less of an issue so closing the comment.