Severe cracks and pops

I’m running Mixbus, but from what I understand, this question belongs with the Ardour part of the program.
With pretty much everything I do, I’m getting severe cracks and pops, that are louder than the actual signal. When I listen a mix, but also when recording and those cracks and pop end up on the recorded track, so it’s not just the output signal to the monitoring system.
When I listen to the separate tracks in, say iTunes, there’s nothing wrong with them, so it must be happening in Mixbus itself.
Anyone who has some insight, or advise on this matter?

Cheers!
Maarten

What plugins are you using? Do the noises still happen if you disable the plugins?

What buffer size are you using in the Audio/MIDI setup dialog?