I am getting an audio delay in headphones when recording even with buffer on lowest setting. In low latency mode Logic Pro will not record audio at all.

Also meant to ask,when you say Logic won't record MIDI/Logic Instruments or Audio?

If audio is there a waveform with no sound? Or MIDI notes with no sound?

Low Latency Mode disables plugins that exceed a latency limit set in Logic's preferences audio.

You most likely have a plugin on the Master Bus that is being disabled. Open the mixer window (command 2) with Low Latency mode enabled, look for a master bus plugin colored orange (in my older version) save the plugins settings and remove it from the bus. **You may not have to remove it, try disabling first. It may have been that plugin which was causing the headphone delay, however, if there were several orange plugins on mixer channels record with LLM enabled. Never leave LLM on, it's only used when recording.

Look up LLM in the manual, if there's any confusion as to it's function.

**In older versions of Logic Disabling the Latency causing plugin did not remove the latency.