Background camera doesn't render on mobile.

Hi there!
I have been working on a 2d mobile game for some time now. The scene is made with two cameras. One for the foreground and one for a parallaxing background. It has worked fine until a day ago where the background camera now only renders a black color on mobile (iOS). It works fine on standalone and in the unity player.
I have been playing around with skyboxes and importing 3d elements, the last day and think I maybe could have turned on something wrong.
If I set the background layer to render on top, it shows up fine on mobile. with parallax. But of course it covers the actual game then.
Any ideas what could be wrong?

Thank you

@ RuneSoegaard
are you using any shader for parallaxing Background ?
if its working on Unityeditor then it may issue with Shader which not Support on device

The secondary camera renders fine on mobile when it’s in front of the main camera, just not when it’s behind…
I figures out that when I switched off the image effects on the main camera, the background camera will render aswell…
The image effects used to work fine… Maybe there’s a problem with image effects and skybox/reflections on multiple cameras?